Katelyn is a cosplayer ("costume player") who dresses up as her favorite superhero, Trinity Infinity, for a comic book convention. While faking a flying shot for a television news crew, she has an accident, and when she returns to consciousness she believes she truly is Trinity Infinity. Katelyn's friends Silvia and Lily--who each take turns dressing up as Trinity Infinity's sidekick, the lovable rogue Element 47--recreate scenarios right out of the pages of the comic books in order to get Katelyn through her daily life: going to the ATM is hacking a weapons console, driving a friend to a job interview is capturing a supervillain, and going to work is an undercover assignment. Paul has an unrequited crush on Katelyn and helps by donning the costume of Necrocide, one of Trinity Infinity's rogues' gallery. When Paul's jealous ex-girlfriend Morgan gets into the game by dressing up as the arch-nemesis The Wretched, that's when things spin out of control.