Has the major star of a TV series ever spent so much time off-screen for strictly creative reasons? Damian Lewis only appeared in one of the first seven episodes of Showtime’s Homeland season 3 this fall. Then, on Sunday, his character Nicholas Brody came back to the foreground in a riveting hour. The episode depicted Brody withdrawing from heroin and then was getting built back up by a special-ops team charged with preparing him for a dangerous assassination mission in Iran. Despite winning an Emmy for his role on the show last year, Brody’s off-screen time reflects the conundrum faced by Homeland writers after they spared Brody’s life last season: How best to fit a falsely accused terrorist who fled the country into a Virginia-based story about a CIA case officer?