K: SEVEN STORIES "MEMORY OF RED - BURN -"

It is the beginning of December. Anna Kushina’s birthday is coming up, so the boys of HOMRA decide to celebrate by preparing a surprise party for their little princess. Tatara Totsuka, the only clansman capable of keeping the destructive power of the Red King, Mikoto Souh, in check wants to do something special and film a video for Anna's birthday. Meanwhile, the new Colorless King sets his plan to devour the other kings in motion... — Description from AniList community (anilist.co).