Harold Perrineau and Cynthia Watros, <i>Lost</i> Harold Perrineau and Cynthia Watros, Lost

Unlike most of the other dead characters who have stopped by for Lost's final season, Harold Perrineau's Michael makes a return to the island, in part to unlock a mystery.

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"I think they brought everybody back so they can answer all these questions," Perrineau tells TVGuide.com of his appearance Tuesday night (9/8c, ABC). "I got to go back and answer one of the bigger questions — not necessarily about Michael, but one of the bigger questions about the island."Michael, who Perrineau assures us is most definitely dead, is also on a mission to help Hurley (Jorge Garcia

), the island's resident ghost whisperer. "Hurley's in a position that he's not comfortable being in now the he's sort of a leader," Perrineau says. "There are a bunch of things going on, and Hurley has to step up a little bit. So Michael's helping him do that."

Also appearing to Hurley is his unrequited love, Libby (Cynthia Watros), who Michael shot and killed in Season 2. Perrineau says everything Michael did after that — including his self-sacrifice on the freighter in Season 4 — has been in search of redemption.

Lost: How will Michael and Libby return?

"[What he did] on the freighter is the only redemption I guess Michael is going to get," Perrineau says. Nevertheless, Michael will have a chance to make amends for killing Libby."I did get to apologize," Perrineau told us in February. "And every time I did it, it was really emotional. There was something really nice about it. It's not just apologizing to her, but an apology to Hurley."Perrineau says he loved having the opportunity to shoot scenes one last time during the final season and that he's pleased with his character's coda."It's the last season, so everything feels nostalgic," he says. "The first year, you got introduced to characters that you fell in love with. Through the years, it's been this big story, and I liked that. But [those characters] have come back, and I think that's a really great thing for the fans who really did love those characters from the beginning. It's a great little bookend to at least get to say, 'OK, goodbye, Michael.'"(Additional reporting by Natalie Abrams)