Hina Tsurugi and her family have just moved to a quaint seaside town. Hoping to savor the sight of the peaceful ocean, Hina stumbles upon a girl named Yuuki Kuroiwa—an upperclassman at her new school—who invites Hina to join her in fishing. Hina reels in an octopus, which falls onto her; being afraid of bugs and big creatures, she panics and begs Yuuki to remove it from her. Yuuki sees this as an opportunity to force Hina to join the schools Breakwater Club—a club where members gather, catch, and eat various types of marine life as their main activity.