Marnie needs space after an argument with Desi and while on her walk, unexpectedly sees someone from her past.
Newly discovered details about the mugger of Valen's mother, a joint-custody request from Miller's ex and brewing legal hurdles for Rush vex those team members as they attempt to solve the 1983 murder of a graffiti artist.
Holmes and Watson discover a connection between a clown's murder and the creation of a weaponized virus; Bell's new love interest's ex targets him.
Sipowicz has to make some tough decisions as he starts a new chapter in his life.
Peter and the Haitian try to get rid of Arthur Petrelli for good but are interrupted by Sylar; Suresh has a breakthrough with the formula.