Nagiko's life unravels in a single day: her employer goes bankrupt and her longtime boyfriend dumps her. Feeling completely adrift, she unexpectedly runs into Kouhei Samegawa, a childhood friend she hasn't seen in years. While they catch up, Kouhei stuns her with a sudden marriage proposal. Despite the impulsive nature of the offer, Kouhei proves to be a clumsy, gentle, and deeply devoted partner. As an elite officer in the Japanese Self-Defense Force, his daily training leaves him brimming with energy, and his affectionate declarations are constant and sincere. Nagiko, initially bewildered, finds herself slowly won over by his earnest sweetness. Their newlywed life blossoms, but tension arises when Nagiko's obsessed ex-boyfriend Hiroyuki begins making suspicious moves, threatening the fragile happiness they are building together. The story follows Nagiko as she navigates the whirlwind of a sudden marriage, learns to trust again, and discovers whether the overwhelming adoration from her childhood friend is the real love she never expected.