Wally and Bez have survived a city bent on slaughtering them and a vengeful demon stalking them inside a dimension-traveling villa. Now, these two must enter Hell itself in order to save the world. Well, all the worlds, actually.

Life in their private oasis has allowed Wally time to train his newly acquired devil's essence. Bez has also learned to accept the calmer elements of the day-to-day without fear of looming threats. But news of Wally's Diabolic ascension has traveled, and now, he's invited to step into the Hell realm of one of the mightiest devils to reign over the universe. If he declines the invitation, it means signing a death sentence for everyone in their world as devils don't take kindly to rejection. But one misstep in Hell will cost Wally and Bez their lives.

Bez refuses to lose Wally. He'd much rather see the world burn than risk Wally's life, but since his insufferable boyfriend insists on doing the so-called right thing, Bez serves as his guide in Hell. There's not much Bez can do against a devil, but he can protect Wally from saying or doing something that'll offend. In order to survive, they'll have to flip their roles: Wally will have to walk into Hell with the confidence of a devil and take charge in a way he's never done before, while Bez will have to hold back his impulsivity and strategize their way through this deadly party.