A recent organ-donor wants to console his grieving fiancee, and Melinda connects her with the man who is the heart recipient.
Patrick and the team investigate when a mayor's aide is murdered; Van Pelt and Rigsby make an announcement.
Oliver confronts a new threat when bombs start to go off in Starling City…planted by a man named Shrapnel, who's targeting Sebastian Blood's Unity Rally.
Following Slade's return and his promise to make good on his threat to destroy Oliver's loved ones, Oliver focuses all his energy on preparing for battle with his former friend.
Marks on a female corpse on a beach lead Horatio to think the perpetrator is a serial killer who bites victims; Calleigh and Delko investigate a murder at a motel pool.
