NBC has posted the official write-up for Chapter Fifteen titled “Run!” For those who are paying attention you may remember the title that was floating around since last year was “Nothing to Loose”. Without further ado, here’s the write up:

AS MATT AND SURESH FACE GRAVE DANGER, THE SCANDALOUS TRUTH ABOUT CLAIRE’S REAL FATHER IS REVEALED — CHRISTOPHER ECCLESTON (”DR. WHO”) AND JESSALYN GILSIG (”NIP/TUCK”) GUEST STAR — While the scandalous truth about Claire’s real father is revealed, her adoptive mother (guest star Ashley Crow) faces a crisis. Matt (Greg Grunberg) takes a job as a bodyguard for a crooked attorney (guest star Aron Malsky), which puts him in the crosshairs of Linderman’s new assassin. Hiro (Golden Globe nominee Masi Oka) and Ando (guest star James Kyson Lee) return to Las Vegas to find the sword, but get sidetracked by a damsel in distress (guest star Missi Pyle). Suresh (Sendhil Ramamurthy) finds someone on the list and unknowingly puts himself in grave danger. Meanwhile, Simone (Tawny Cypress) turns to some unlikely help in her and Nathan’s (Adrian Pasdar) struggle to find Peter (Milo Ventimiglia). Santiago Cabrera, Noah Gray-Cabey, Ali Larter and Leonard Roberts also star. Jessalyn Gilsig, Jimmy Jean-Louis, Lisa Lackey, Zachary Quinto and Cristine Rose guest star.

Source: NBC