As the boys search for a new sound for ZO2, an old ghost reappears and throws the makeup of the band into question; Dave Navarro is back. But once the boys get past the fact he left them in the lurch and nearly ruined their careers, they decide to audition him to see if he's ZO2 material. Meanwhile, Dina runs smack into an old ghost of her own. The one that got away: rock legend Daryl Hall. Daryl Hall and Dave Navarro guest star.