As a child, Raku Ichijo made a secret promise with his childhood sweetheart, keeping a pendant as a memento while his love took the key. He dreams of one day meeting his past love, but years later, reality smashes his hopes when Chitoge Kirisaki accidentally knees him in the face. Though Raku's a normal high schooler, his family heads the notorious yakuza gang the Shuei-Gumi faction.
Sebagai budak, Raku Ichijo mengikat janji rahsia dengan buah hati zaman kanak-kanak, menyimpan loket kenangan sementara kekasihnya memegang kunci. Dia idamkan berjumpa dengan cinta lampaunya suatu hari, namun banyak tahun berlalu, realiti memusnnahkan harapan ketika Chitoge Kirisaki tiba-tiba melanggar mukanya. Walaupun Raku hanya murid sekolah tinggi biasa, keluarg-anya mengetuai geng yakuza, puak Shuei-Gumi yang terkenal jahatnya.