Shiawase ni Nari na.

On the first day of a part-time job at a bookstore, the trainee is immediately drawn to Kai, who is strikingly handsome. The next day, they impulsively ask him out, and he accepts without hesitation. Confused, they double-check their intent, but Kai responds with a passionate kiss, confirming their assumption. This sudden attention leaves them overwhelmed, but soon they hear a troubling rumor about Kai: he is known to form casual relationships without allowing them to become serious.