“TKO” is episode fourteen of season one of Babylon 5.
A liner arrives from Earth and two men enter the station. One man, a rabbi, says goodbye to the other, a Mr. Smith, saying that he has been an interesting travelling companion.
Garibaldi sees a drug deal going down and knocks the human to the floor. Whilst Garibaldi’s back is turned, the human gets up with a knife, but is knocked down by the man, Smith, from the liner. Walker Smith is an old friend of Garibaldi’s; a boxer, he was on his way to the world title when he was disgraced.
Ivanova is reading in her quarters when someone comes to her door. It is the rabbi from the liner, Koslov, and he’s an old friend of hers. Ivanova’s father had died in “Born to the Purple” and she didn’t make it back to Earth for the funeral, and she hasn’t sat shiva for her father. Rabbi Koslov was given a legacy by her father, and he’s brought it to the station for her. Ivanova says she has no time to sit shiva.
According to Walker, he was told that it wasn’t his time to win the world title, and that he should retire for a few years. Having struggling hard to get to the match, he not so politely told them to stuff it, and wound up framed as a result. Walker hasn’t had a legitimate fight in two years, so has come to Babylon 5 to be the first human to fight in the Mutai. Doing so will make him so well knows that he will get another shot at the title.
Garibaldi thinks this is a bad idea. The Mutai is dangerous and many have died, and many more crippled, fighting in it (it looks to be a sort of MMA sport). Smith does not make a good impression initially, and is told that he can’t compete. However, one of the aliens tells him of a way in which he can compete. Something that makes at least a few aliens really unhappy.
Rabbi Koslov approaches Commander Sinclair to ask if Ivanova can have time to sit shiva for her father. Sinclair didn’t even know he was dead, and willingly grants her time off. Ivanova does not take this well; it isn’t really a lack of time that has stopped her from sitting shiva, but the fact that there was bad blood between her and her father.
So, Walker is fighting in a dangerous alien sport and Ivanova needs to come to terms with what her feelings for her father actually are.