Still upset over what happened at class, Jun goes to watch a pro wrestling match only to find Keima sitting at her seat thanks to Elsie making a copy of her ticket. As she is forced to sit with him to watch the match, Jun wonders why the class won't let her help them, which Keima then asks her why the girls basketball team disbanded when she was captain and correctly concludes that it was her idealism that forced the other members to quit and despite claiming she was trying to help the team for them, she was actually helping them for herself which Jun leaves the match in anger. Despite this, Keima concludes it's time to capture her heart. Later, Jun tells the class she has entered them for a marathon hoping to help them bond, but instead they refuse, feeling that she's trying too hard on them, which leaves Jun disappointed and tells the class how selfish they are before running away. As the class bad mouths Jun, Keima unexpectedly calls out on their behavior and disappearing before they confront him. As Jun arrives at the old girls basketball team locker room, Keima confronts her, telling her despite claiming to have changed in order to teach her idealism to others, she still hasn't changed at all. As she runs away into the school gym crying and wondering why people won't let them help her, Keima consoles and tells her to not give up and try harder as it will finally make them accept her idealism. Just then, the whole class arrive in the gym to apologize to Jun much to her joy. Unknown to Jun, Keima knew what was going to happen so he planned with Elsie to have the class to start hating him after Jun left and made them worry about her after she was gone. As Jun's time as a student teacher comes to an end, Keima sees her off and asks her to come back which she promises to become a better teacher and kisses him, finally expelling the spirit inside of her.

Keima explains to the audience how he has captured fourteen girls and two unique girls after the last season. Meanwhile, Kanon is preparing for her school tests, but ends up talking with her split personality, Apollo, who claims to be a goddess. The next day, Keima and Elsie meet up with Tenri and within her, Diana. Diana wants Keima to marry Tenri as Tenri's love for Keima increases her powers, which he refuses. When asked to explain what she is, Diana reveals she is a goddess, one of the Jupiter Sisters, who helped the New Demons of Hell against the Weiss, when they attempted to take over the three realms of Earth, Heaven and Hell, and control all souls. After defeating them, the Jupiter Sisters sacrificed themselves by sealing themselves together with the Weiss, but they escaped ten years ago. Diana asks Keima to help find her sisters and reveals they reside in his past conquests, who did not forget their memories with him.

As they head to Ayumi's location, Chihiro tells Keima he should tell the truth to Ayumi as unknown to Keima, she already told Ayumi that he was trying to win her heart for something important. At the harbor, Keima tell Ayumi he will honestly tell the truth if she ask anything before continuing their wedding.