Toji Seryo is a popular first year high school student. It's well known that Toji Seryo will date anyone that confesses their affection for him on a Monday, but he will break up with that person by Sunday. Yuzuru Shino is a third year student at the same high school. He looks pretty, but all of his former girlfriends end up dumping him. Yuzuru Shino becomes curious about Toji Seryo. On a whim, half serious and half joking, Yuzuru Shino asks Toji Seryo to date. The film is based on a comic. Part 1 follows Monday to Thursday. Part 2 follows Friday to Sunday.

Plain, timid and obsessed with jellyfish, Tsukimi is a far cry from her idea of a princess. Her tepid life as a jobless illustrator comes complete with roommates who harbor diehard hobbies that solidify their status as hopeless social rejects. These wallflowers run a tight, nun-like ship, but their no-men-allowed-not-no-one-not-no-how bubble is unwittingly burst after Tsukimi brings home a rescued sea jelly and a beauty queen... who's actually a guy. When the threat of losing their cozy convent inspires this glamour boy to turn the neurotic entourage into a portrait of success, will Tsukimi take her chance to bloom, or will she end up a hot mess?