It was used as the second ending theme song for the anime series Qualidea Code.

[3] On 26 March 2016, Marvelous revealed in event at the AnimeJapan 2016 event about more details of the anime series Qualidea Code, including the ending song "Yakusoku -Promise Code-" that would be sung by Garnidelia.

[4] The music video for "Yakusoku -Promise Code-" was directed by Shin Okawa.

Some scenes sometimes show toku playing piano and MARiA singing in the warehouse, with both of them wearing Yukata.

The video end when the girl takes her friend's hand from the virus, saving her life.