00:50HeroesSeries 4Episode 18: The WallBBC Two Duration: 40 minutes Audio described Sat 8th May 2010, 00:50 on BBC Two Northern IrelandAvailable for yearsWatch nowWhile Peter tries to save his nemesis, Lauren goes after Samuel. Claire learns the dark secrets of Noah's past.ContributorsNoah Bennet/HRG:Jack ColemanMatt Parkman:Greg GrunbergSamuel Sullivan:Robert KnepperTracy Strauss:Ali LarterHiro Nakamura:Masi OkaClaire Bennet:Hayden PanettiereNathan Petrelli:Adrian PasdarGabriel Gray/Sylar:Zachary QuintoPeter Petrelli:Milo VentimigliaGretchen Berg:Madeline ZimaGenresDramaSciFi & FantasyBrandHeroesSeriesHeroes: Series 4 Source: BBC Online