Season 1 of Jack o' Frost premiered on February 17, 2023.

Illustrator Okusawa Ritsu and salesman Ikegami Fumiya met at an old coffee shop and eventually fell in love and lived happily together. However, a misunderstanding arises between Ritsu, who lives freely, and Fumiya, who is swayed by it. After a fight, Ritsu leaves the house and is involved in an accident. Upon awakening, Ritsu had lost the memory of Fumiya. Wanting to start their relationship over from scratch, Fumiya hides the fact that he was dating Ritsu and resumes their joint life. However, Ritsu asks him to take him to a familiar place in order to regain his memory. Fumiya is reluctant, but the two of them start a journey to follow the trajectory of their relationship. The coffee shop where they met for the first time, the riverside road they always strolled, the places they both traveled to before dating.

Sweet and bittersweet memories, the time they spend together haunts Fumiya's mind. Ritsu, on the other hand, finds himself gradually becoming attracted to Fumiya again.