Transformers 4 could see the robots heading into a different dimension, director Michael Bay has hinted.
The filmmaker, who directed the previous three films and is set to take control of the fourth - and his final - instalment in the series featuring the giant robots, also said that the upcoming follow-up is not a "reboot".
"I want to go a little off but I don't want to go too sci-fi. I still want to keep it grounded. That's what works in these movies, that's what makes it accessible," he suggested to the Los Angeles Times.
He added: "It's not a reboot, that's maybe the wrong word. I don't want to say reboot because then people will think we're doing a Spider-Man and starting from the beginning. We're not. We're taking the story that you've seen - the story we've told in three movies already - and we're taking it in a new direction. But we're leaving those three as the history. It all still counts."
Michael, who is currently working on comedy action film Pain And Gain, has commissioned Ehren Kruger to write the screenplay for Transformers 4, which is scheduled for a 2014 release.
"I met with the writer before I went off to do Pain And Gain and we talked about a bunch of ideas. We let that simmer for a bit," he said.
"He's been thinking about stuff and now we're getting back together next week to see what we've got and to see if it gels."
Michael is ready to hand over the Transformers franchise to another director.
"Here's the thing, it's tough to find someone who's done these kind of movies and to have the complication of creating the new stuff that needs to be in this movie - not just characters but a new type of action, I hope - and that's a lot for someone new to bite off," he continued.
"And so after this one I will leave it in the best hands possible. That's the plan."