Edward Carnevale

When Holmes and Watson investigate a clown's murder upstate, they discover a connection between his death and the creation of a new weaponized virus. Also, Watson helps Bell when he's targeted by his new love interest Chantal's (Chasten Harmon) ex-husband in attempt to sabotage her career at the district attorney's office.

Needing space after a fight with Desi, Marnie goes for a walk and has an unexpected run-in with someone from her past.

Hoping to find a way to stop Arthur (guest star Robert Forster), Hiro (Masi Oka) and Claire (Hayden Panettiere) band together and travel back in time 16 years to when Kaito (guest star George Takei) gave baby Claire to H.R.G. (Jack Coleman). Meanwhile, Peter (Milo Ventimiglia) and the Haitian (guest star Jimmy Jean-Louis) team up to finish off Arthur Petrelli for good but are interrupted by Sylar (Zachary Quinto). Elsewhere, in the lab, Suresh (Sendhil Ramamurthy) has a major breakthrough with the formula that will likely change everything. Ali Larter, Cristine Rose, Greg Grunberg, Adrian Pasdar and James Kyson Lee also star. Jessalyn Gilsig, Ashley Crow, Tamlyn Tomita and Chad Faust also guest star.

While investigating the 1983 case of a tagger who died from a fatal dose of spray paint down his throat, Rush, Valens and Miller each contend with vexing personal issues.

When a dying man with a long-standing vendetta puts a hit out on Josef, Mick discovers a secret his best friend has kept from Mick for over 40 years -- and the real reason Josef believes Mick and Beth can never work.