On the day he was going to confess his feelings to his childhood friend, Chitori Yaku, Haruto Renma’s entire world turns upside down when warrior alien princess Lan arrives on earth, challenging Chitori to a duel. In a desperate attempt to aid Chitori, Haruto ends up grabbing Lan's tail, which by her people’s law. . make him her betrothed. Now with angry former suitors, romantic rivals lining up at the door, Haruto has no idea how he'll ever be able to confess to Chitori. . .or stay alive.