Peter and Cleo may be at fault when a police officer shoots and kills an old woman with dementia. Carter misinforms Rena and tells her that he and Abby had a past liaison. April Fool's Day causes the staffers to play pranks on each other; Malucci gets the worst of it when Kovac injects him with Haldol, rendering him useless for the rest of the shift and getting his hand glued to his forehead while asleep. Corday endures a particularly long surgery just to prove that she can despite her pregnancy. Greene treats three young students who have been huffing carpet cleaner. Luka treats another pregnant teenager, who wants the comfort that a child will bring her.