With Michael Bay returning as director, a buzzy, unknown young actor in the lead and Mark Wahlberg anchoring it all, "Transformers 4" is moving full-steam ahead, but with talk of leaving behind many elements from the first three films, the next adventure of the Autobots remains largely a mystery.

That's exactly why MTV News' Josh Horowitz grabbed producer Lorenzo di Bonaventura on the red carpet for Steven Soderbergh's "Side Effects." When we spoke with di Bonaventura around this time last year, he confirmed to MTV News exclusively that Bay would return to direct a fourth "Transformers" movie, a reboot, scheduled for 2014.

A few weeks ago, Bay enthusiastically revealed that the next movie kicks off a new trilogy, but did not comment on whether he will stay on to direct the last two installments. While excited about the prospect, di Bonaventura couldn't say what Bay's roll will be in the rest of the series. "I can't speak for Michael. I hope he would [direct the next two]. It would be great, but it's certainly something in our design of this," he said. "It's going to be an ongoing story, so the possibility, again, as long as the audience shows up for us, there's a lot of story still to be told."

Since studios toss the term "reboot" around with abandon, the extent of the reset on "Transformers" is still unclear. From how di Bonaventura describes it, the new films will introduce many new characters and settings, while staying true to the tone of the first trilogy. "There's a lot of new elements. I wouldn't say we've completely changed this world, and yet it's completely different," he said. "There are new characters, new situations. I don't think we revisit a single location. Michael really has a great way of approaching this thing."

But what about Sam Witwicky, the hero of every "Transformers" movie up until now? Di Bonaventura leaves the door open for a cameo, but he does not see it right now. "I don't believe that would be true. You never know. Things are not set in stone, and if something evolved and that came naturally. That wouldn't be the intention," he said. "The intention is this is new world, with new characters, with Mark Wahlberg leading us. It's a different movie, but a lot of the things that you love about the other ones are joining the ride."

Check out everything we've got on "Transformers 4."