Armin, a complex young man struggling with bipolar disorder, finds solace in his relationship with a kind-hearted girl named Y/N. However, Armin's jealousy and possessiveness threaten to tear them apart, especially when his ex-girlfriend Annie re-enters the picture. As Armin rises to fame as a heroic titan fighter, Y/N must navigate his fame, fan girls, and Armin's all-consuming obsessiveness - earning him the nickname "Her B.O.B." (Bipolar Obsessive Boyfriend). But through his episodes, Y/N has discovered a unique way to calm Armin down- by making him climax and then allowing him to sleep, which restores his normal, sweet self afterwards. Yet this delicate balance is tested as Armin's disorder deepens with his newfound fame and relationships, ultimately fighting to keep their passionate, confusing, relationship afloat.