Robert John Burke, Kevin Chapman Photo

From: Photo Flash: PERSON OF INTEREST's 'In Extremis,' Airing 4/25

On PERSON OF INTEREST's upcoming episode, titled 'In Extremis,' when a luminary in the world of medicine is poisoned, Reese and Finch have just 24 hours to determine the deadly toxin he was given and find the person behind the attack. Meanwhile, Detective Fusco's past corruption catches up with him when an informant gives the Internal Affairs Bureau the crucial information they need to send him to prison, on Thursday, April 25 (9:01 - 10:01 PM, ET/PT) on CBS.