Matthew Gideon is the Captain of the IAS Excalibur. He was specifically chosen by Interstellar Alliance president John Sheridan because he would be willing to take chances and would not let diplomacy get in the way of completing the mission. He is also reputed to have been in more battles during peacetime than most officers face in a major war. 
In 2259 Ensign Gideon first posting was on the EAS Cerberus, he was sent out in an EVA suit to fix the engines when the ship was attacked and destroyed by a Shadow Hybrid vessel. However, Gideon let it slip at one occasion that he believed that the Cerberus wasn't attacked by accident, insinuating a conspiracy. Gideon was the sole survivor and was left floating in Space. Gideon was picked up by the Technomage Galen, who later dropped him off at Omega VII.  Galen along with his fellow Technomages were not in that region of space by coincidence, they were themselves tracking the moments of the unknown Shadow tech vessel.
By 2267 Captain Gideon was the commanding officer of an Explorer class ship. When an emergency call went out to all Earthforce ships he rushed back to Earth only to find that the fleet of ships that protected the Earth against the Drakh were all either damaged or destroyed. He also found out that the Drakh had released a plague on the Earth.
He was then called to Mars where he was reassigned to the Excalibur. He was going to receive a whole new crew to with the best Scientists and Archaeologists that were available. When he demanded that Lt. John Matheson be on board too, he faced resistance from Senator McQuate, as Matheson was a Telepath. Then he meets Dureena Nafeel, who was demanding to come along. He tells Senator McQuate that he wants her on his team or he can find another CO for the IAS Excalibur. Senator McQuate allows Dureena to join the crew, although in truth he had no choice in the matter as ISA President John Sheridan personally selected Matthew Gideon to lead the mission when he gave the Excalibur to Earth Alliance.
On their first cruise, they get a distress call from a colony that is under attack by the Drakh. Gideon and Dureena go down to the planet with a rescue team and save a team of Archaeologists whom work for IPX. Their lead Archaeologist, Max Eilerson, has a knack for figuring out languages and how to work Alien Technologies, so Gideon asks him to join the crew of the IAS Excalibur to save Earth from the Drakh Plague.
The Excalibur then proceeds to a colony of people who had been living with out any modern advancements for about 80 years. They found out that a mineral in the ground was keeping them unusually healthy. Earthforce was trying to harvest the mineral but the workers kept on seeing and experiencing strange phenomena. One such example of which is the engine on a shuttle being replace with a substance resembling peanut butter. Gideon and Galen go down to the planet to investigate and find a Technomage down there that Galen knows. They tried to convince Earth Force to stop mining but to no avail. Then some of the towns people began getting sick. They figured out that the mining was releasing the mineral in to the atmosphere which was overexposing them to the antiviral toxin. This did not convince Earth Force to stop so the Technomage created an illusion of him trying to destroy the ships in orbit. Earth Force tells Gideon to kill the Technomage and it appears he has but actually he destroyed the mining operation. The Technomage leaves the planet and Earth Force mines somewhere else.
The Well of Forever
The Excalibur then takes on a telepathic monitor that was going to check up on Lt. Matheson. Meanwhile Galen convinces Gideon to go off the beacon in Hyperspace, in search of the Well of Forever. To achieve this Galen patches his guidance system into the Excalibur's system and they go looking for the Well of Forever. Meanwhile the telepathic observer tells Gideon that Lt. Mattheson will have to go back to Earth for an inquiry. Gideon doesn't like this and tries to get the monitor to change his mind but he wont. When they got to the supposed location of the Well of Forever it wasn't there. Galen then takes control of the ship and goes to find it with out Gideon's permission. They find the Well and Galen goes out and land on it. Gideon follows and finds out that Galen was burying his lover. They go back to the ship and Galen says he will never betray Gideon's trust again. Then Gideon tells Dureena to go and think about planting a bomb when she is near the telepathic observer. The observer tells Gideon about this, Gideon then tells him that if he forgets about Mattheson he will forget that he violated someone's privacy. So Matheson is allowed to stay on board and doesn't have to go back to Earth.
Gideon is then sent to a planet that had no value in any kind to go get some people who reportedly had the plague. When they get there they find the ship and the crew, and take a blood sample from their leader. They find out that they infected with the plague. Gideon reads up on these people in some Top Secret Earth Force files and finds out that they have cybernetic implants. Chambers calls back and says that she ha found that the food the colonists were eating was contaminated with the plague. Gideon then realised that they had escaped Earth in time, but their food supply had been contaminated with the plague, by a General in Earth Force. Then some of the colonists take Chambers as a hostage. They try to escape but Gideon stops them, and has them get out of their ship before he destroys it. He then allows the people to stay on the planet just as long as they don't leave. He Places a beacon in orbit informing ships that the planet is infected with the Drakh plague, and the leaves in the IAS Excalibur.
Gideon is then ordered to Mars to attend a conference set up by Dr. Stephen Franklin, where the Excalibur's CMO Dr Sarah Chambers is the Key Note Speaker. When he got there he meets Lochley who is in charge of the conference. They have an argument about how to run security. Then a man who was supposed to attend the conference is killed. Giedon & Lochley figure out it was done by a doomsday cult. When they take the body up to be autopsied by Dr. Chambers, Trace says he knows the man from his days back as a Foundationist. Lochley tries to question him further but Gideon doesn't let her. Gideon then asks to have dinner with Lochley. She agrees and they talk a little about Sheridan, Lochley figures out that Sheridan is Gideon's hero. She then tells Gideon that she was married to him. Then Lochley assigned Gideon to patrol the conference. When Lochley found out who the man from the cult was she tells Gideon. Gideon goes up and interrupts Dr. Chambers speech. He says that they miscalculated the danger and that instead to five years they had a few months. Also he said that this was brought upon them by God for their lack of faith. The guy left and turned off his bomb that was going to blow up the conference. When he went back to their hiding place, Gideon, Lochley, and Mars Security jumped them and killed all of the people in the cult. When Gideon left he said that he would swing by Babylon 5 sometimes just to stop in.
Attempted Alien Takeover
The Excalibur then takes on a pair of PR reps who are going to make the Excalibur more popular back home. Gideon doesn't like this. Three days into this they run into a ship. Everyone on that ship is dead except one person. Gideon sends Matheson on board to check it out. They find the entire crew dead and one person alive in a life pod. They bring it aboard the Excalibur and try to save it. The creature starts to die and a member of the medlab team goes in and tries to save it. It dies but before it does it grabs the crew member and transfers an energy being into her. She then starts to transfer the being to other people so that it could take over the ship. Meanwhile Eilerson cracks the alien’s language and learns of the energy being. He shows this to Gideon and Gideon locks down the sectors that the energy being is in. He then meets with the leader who tells Gideon to drop them off at a nearby planet so that they can colonize it. Gideon declines to do so; he then lowers the temperature in those sections. The alien then starts killing the crew and tells Gideon that if he doesn't come down to them that he will kill more of the crew. Gideon goes down in an EVA suit because he knows that the alien is passed by physical contact, and if he is in an EVA suit he cannot be taken over. He then talks with them and says "As Mr. Eilerson always says: the air is human." He was hoping to get the rest of the crew to depressurize the sectors that the alien were in. They do and they manage to bottle the alien in a body that couldn't move. They then ejected the body and destroyed it. The two PR reps then leave and give the crew new uniforms.
Discovery of Ancient Civilization Infected with The Plague
The Excalibur then goes to a planet that looks abandoned. Eilerson finds some hieroglyphs that the beginnings of formulas for advanced things such as technologies and light alloys. Gideon tells him to look for a cure not for a profit. Then when they find one of the crew dead, Gideon orders the rest of the crew back to the ship while he distracts the incoming enemies. He almost gets himself killed but Galen comes and saves him in the nick of time. They then figure out that there are underground passage ways and areas containing ships from other races. Then when they found the entire race in cryogenic suspension some ships from the planet come and try to destroy the Excalibur. When Gideon tries to move away he finds that their caught in a gravimetric beam. He manages to destroy the beam station with the main gun. Then a hologram appeared. It told them that the Shadows had come to the planet and tried to build a base there when they wouldn't let them they dropped the plague on them. That was 1000 years ago. They have been studying different species by dissecting them to find a cure. Gideon said that if the Excalibur found a cure that they would bring it back to the planet.
Paradigm of Earths Plight
They reach a dead planet that they think the Drakh plague had been. Galen says not to go down there because none of his order had ever gone there and the one who did was killed by what he called a spirit. They go down anyway. Then Dureena brings back a data crystal that she found. Eilerson decodes the crystal and finds that the entire populous was killed in 3 days by something that they couldn't explain. Then some members of the crew are killed. When they sent the dead up to the ship to be autopsied, Dr. Chambers found out that a nanovirus was causing the people to die. Then Galen figured out that it was created by a Technomage. He went down to the planet and went to destroy the Technomage that did this. Gideon told everyone to stay inside and lock the doors because the virus caused people to kill each other and behave erratically. He then went to go find Galen and help him. When he got down to where Galen was he found Dureena trying to kill Galen. When Dureena charges at Galen, Gideon blows the bridge out from under her. She makes it across and Galen throws his staff at the machine. It blows it up and they return to the ship.
Apparent Interference with an Alien Culture
The Excalibur runs into a life pod with two lifeforms inside. When they bring it aboard they find that the aliens know English and dress like them. The aliens think they are being abducted, Gideon asks them how they know English. They tell them that their government was plotting with his government to take over the planet. Gideon didn't know about this and the alien shows them the proof that they have which consists of a picture of a blimp, a picture of Mount Rushmore, and a golf club. The alien came and tried to bring them back but the other two aliens captured him and tried to get away. They managed to get to the bullet cars but were captured. The other alien told Gideon that there really wasn't a conspiracy they only made it look like Earth was interfering because they wanted the blame for the problem put on something else. When he left Gideon went to the planet and drops 20 probes uncovering the conspiracy and containing the interstellar encyclopedia.
Medical Test to Develop a Cure
A senator came aboard and told him that he needs to go back to Earth immediately. He then detected at distress beacon. He picked up the ship and found Capitan Lochley badly injured. Then put her in the infirmary. Then they continued on to Earth. When they got there they were met by a shuttle with Dr. Franklin on board. Apparently they were going to infect a person who volunteered himself. Then they came under Drakh attack. They tried to fight them off but their ship to ship communications link was damaged. Lochley told Gideon that she would tell the Starfuries what to do. Then Gideon got an idea and decided to try to ram the mother ship. When they try the mother ship jumps into hyperspace. Then the Excalibur destroyed it. Gideon then dropped Lochley off at Babylon 5.
- Crusade (13 episodes)