A decade after the events of "Chosen," the Slayer spell remains active, and Spike is undercover in LA. He meets Indira, a young, untrained Slayer who needs a mentor. The situation becomes complicated when an alternate reality's Cordelia Chase arrives, revealing her world is in peril.
Spike must determine if the alternate Cordelia is a genuine ally or an impostor. Cordelia explains the stakes in her dimension, where she is the sole Slayer and the Scooby Gang as we know it never existed. Past relationships and histories are referenced, showing the vast differences in their realities.
The group starts forming a plan to deal with the threat in Cordelia's world. This involves the return of other familiar faces, but the characters quickly learn that years and multiverses have changed not everyone for the better. Tensions rise as they prepare for interdimensional travel.
The heroes split up to tackle different objectives. One team, including a human Anya and a demon Anyanka who have merged in an unusual way, must track down necessary magical items in what remains of Sunnydale. The other team, Spike and Cordelia, focus on saving an injured Slayer.
Personal histories are explored as the characters face difficult truths about their families and pasts. The group contends with Drusilla's growing power in the alternate reality, where she has a surprising ally in Tara Maclay.
The group decides a drastic measure is needed to fight Drusilla's forces: resurrecting their reality's version of Spike. The plan moves forward despite internal friction and external attacks by Drusilla's minions.
Trust issues come to the forefront as the team realizes they might be compromised. They must navigate a difficult path to secure the items they need while facing betrayal and unexpected threats from within their expanded group.
As the final confrontation approaches, the characters are forced to make difficult sacrifices. They deal with a villainous Jonathan and a vampire Giles, culminating in a series of intense events to stop Drusilla's plan from spreading to other realities.
The combined forces face Drusilla in an epic showdown to save the multiverse, the outcome of which will decide the fate of both worlds.