A new film reimagines the "Satsuriku no Deep Blue" story arc from the 1997 Kindaichi TV series. Kindaichi, Miyuki, and Fumi are invited to Deep Blue Island resort by Akane, their senior and the daughter of the president of Aizawa Group. However, their trip is hindered by a group of disguised criminals who have infiltrated the hotel staff in order to assassinate Aizawa Group members. Little do the criminals know, their leader is also present on the island, posing as one of the Aizawa Group members.