Todd Lasance as AFP Liaison Officer Sergeant Jim 'JD' Dempsey and Olivia Swann as NCIS Special Agent Captain Michelle Mackey.Daniel Asher Smith/Paramount+ Tap Here To Add Us Weekly As A Trusted Source Add as a preferred source on Google NCIS: Sydney season 3 ended with one case seemingly closing and another up in the air - literally - but it's the possible romance between Mackey and JD that has fans talking. Warning: Spoilers below from NCIS: Sydney season 3, episodes 19 and 20.