Despite some members' suspicions, Cole manages to survive and fit in, at least for now. The Brotherhood is plotting to take over a powerful communications company by killing its CEO, Pirelli, and replacing him with one of their own shape-shifters. The Charmed Ones manage to save Pirelli but the demon Vornak does take his place. Piper and Prue suspect that Cole knew more about the plan than he let on.
It turns out Prue kept the remainder of the Belthazor flesh in the freezer and they use it to make a potion to vanquish the members of the Brotherhood on the basis that they are biologically linked to Cole/Belthazor. Cole tells Phoebe not to act against Vornak, then turns up at the manor with other Brotherhood members and kidnaps Pirelli. Piper and Prue are convinced that Cole has "turned". Cole doesn't hand Pirelli over to the Brotherhood, but hides him.
When the girls go to vanquish Vornak, he imersonates Cole, but they vanquish him anyway. Next the real Cole shimmers in to tell them it's all been part of his master plan. Phoebe at least is willing to believe him. Cole returns to the Brotherhood, assuring Phoebe that he will be back that evening for her graduation party. However, the Brotherhood are suspicious and knock Cole unconscious. Meanwhile the girls rescue the real Pirelli and the Brotherhood's plot is thwarted. Over at P3 the other two finally accept that Cole was acting for good, but Phoebe's graduation party is spoiled by Cole's absence and her fears for him.