Clash of the Titans.
Ken, Ryu, and Chun-Li are invited to a party by Vega, although Ken doesn't know that it was Vega who sent the letter. Ken and Chun-Li go to the party, while Ryu stays behind at the hotel practicing his Hadouken. When they reach the party, Chun-Li drifts off into a daze, and Ken, realizing that Vega is in the steel deathmatch cage in the middle of the room where the party is being held, accepts Vega's challenge. Vega attacks Ken a few times, as the episode ends.