The series is based on the French-Belgian feature film 'Les Émotifs anonymes' (2010) by Jean-Pierre Améris and skillfully transposes the story into an Asian-Japanese-Korean cultural context without simply copying it.

Directed by Sho Tsukikawa, who was honored by the Japan Academy for his feature film 'Let Me Eat Your Pancreas'.

The film crew consisted of experienced filmmakers, some of whom had previously worked on the Oscar-winning Korean film 'Parasite'.

Lead actress Han Hyo-joo learned Japanese specifically for the role of Hana Lee and stated that speaking Japanese during filming was a major challenge for her.

The series score was composed by the award-winning Korean composer Dalpalan (Ki-yeong Kang).

The series' first two episodes premiered on September 19, 2025 in the 'On Screen' section of the 30th Busan International Film Festival, before its worldwide Netflix release began on October 16, 2025.

The series immediately reached number 1 on the Netflix series chart in Japan after its launch and made it into the top 10 in 31 countries and regions.

International critics such as Liz Kocan (decider.com) and Quinci Legardye (marieclaire.com) praised the series as a sweet yet serious romance drama that provides an honest portrayal of real social anxieties and phobias.