Hell-demon Elsie reveals that high school student Katsuragi Keima, an expert in dating sim video games, has accepted a contract to help capture evil spirits hiding inside real-life girls' hearts.

Elsie transfers into Keima's class and announces she's going to live in his house as his little sister, all for the sake of rounding up the loose souls in the city.

Keima and Elsie follow their next target, resident rich girl Mio Aoyama, home and discover that she actually lives in a run-down apartment. Keima offers to be Mio's new driver as the first step in getting close to her.

Keima takes on a buggy game that everyone is complaining about and enlists a reluctant Elsie to help him avoid the traps so he can rescue the heroine Sora Asuka.

Current pop idol Kanon Nakagawa is actually a student at Maijima Academy and is coming back, causing an uproar. Keima doesn't recognise her as an idol, but Elsie does see the evil spirit hiding inside her.

When Keima treats Kanon coldly, her body begins turning invisible and it seems to be related to the loose soul inside her. As Elsie investigates, she discovers something that happened in Kanon's past.