Nana ("no-name" in Japanese) has no memory of his childhood earlier than age 12 when a store owner took him in and gave him a name that meant "no-name" in Japanese. Mitsuha is on a quest to find a missing childhood friend. The two meet when Mitsuha ends up crashing at Nana's place at the insistence of a mutual friend. At first Nana loathes the very existence of Mitsuha. However, he gradually warms up to his sincerity and kindness and finds happiness in awakening beside him. Can their budding relationship help Nana come to terms with his unknown past? Are Mitsuha's feelings real, or is Nana simply a replacement for someone he lost long ago?