《不可遗忘》第五季获得预订，将于2023年播出，Sanjeev Bhaskar回归出演DI Sunil 'Sunny' Khan，因第四季最后一集中发生的事件，Nicola Walker将不会再出演DCI Cassie Stuart这一角色，本季中Sunny的新搭档是由Sinéad Keenan扮演的DCI Jessica James，她将接替Nicola Walker的角色和Sunny一起调查一桩全新的旧案。

When Dylan Wilson purchases a collection of seven paintings to hang in his wealthy estate, he has no idea what horrors he has unleashed for himself, his wife; Gina, his college son; Louis, his teen-age daughter; Donna, and his two little kids. Only Father Mendale knows what evils lurk inside this deadly art and the history of Dorian Wilde; the artist who made a pact with dark forces when he created these paintings that represent the seven deadly sins. Now, anyone who comes in contact with these pictures are corrupted by Pride, Lust, Gluttony, Sloth, Greed, Envy, and Wrath. It's up to Father Mendale and Louis' girlfriend; Kim to save Dylan and his family before they are all destroyed by the Art of the Dead.