Season 7, Episode 1, "It Takes A Village"
In Season 7, Prentiss returned when Ian Doyle posed a risk to his son. Naturally, the BAU was shocked, but glad that she was alive.
Together, the team was able to save Doyle’s son and close the case, but their methods in doing so came under scrutiny by the Board of Directors. In the end, it was Emily’s testimony that saved all of their jobs.