The "Transformers" franchise might just go back to its lighter mood on the fifth iteration, after one of the cast members said the movie was becoming darker and darker.

"The last Transformers movie 'Age of Extinction' was a soft reboot of the franchise as the films introduced new characters and moved in to a darker storyline," Air Herald explained, saying that the film was a flop among critics but a box office hit, nevertheless.

With that curious trend, Peter Cullen — the voice of Optimus Prime — observed that the movie was getting apocalyptic, per the report. With "Age of Extinction," he reportedly refused to say one line because it just did not feel right.

"The franchise is now in a strange transition period, with director Michael Bay (he directed the past four movies) moving on and some concerns about where the plot is headed for Transformers 5," Air Herald noted.

According to the report, Cullen put his foot down, telling those concerned about his desire that the storylines of the fifth and sixth editions of the Transformers movies return to their original formula.

The last movie was just so bad that it is also leading this year's Razzie nominations for the worst flick of 2014, noted Enstarz. That is even as it is among the highest-grossing movies internationally, earning $845.3 million.

The International Business Times described a possible plot: "The much anticipated sequel may feature Optimus Prime's journey into outer space, while his army of Autobots will stay on earth to protect human kind from the Decepticons."

Master Herald, meanwhile, noted that it might become a "G.I. Joe"-like movie.

The Christian Today said, "...[P]lot speculations and suggestions are also being developed fervently by fans. Many think that new species of both mean and likable mechanoids will invade Earth, some to increase the Decepticons' level of evilness while the others to uphold good with the Autobots."

The project, expected to be released in the summer of next year, might be directed by Jonathan Liebesman of the recent "Teenage Mutant Ninja Turtles" and 2011's "Battle: Los Angeles," tThe International Business Times added. Christian Today explained that he was chosen by Hasbro Studios because he was trained by Bay.

Mark Wahlberg, who starred in the "Age of Extinction" that premiered June 2014, bade goodbye to the sequel, reported Master Herald, explaining that Dwayne "The Rock" Johnson and Bruce Willis were being seen to lead next.

However, Christian Today said Wahlberg has already confirmed his return as the mechanic, inventor and single dad Cade Yager. Megan Fox and Shia LaBeouf may also make a comeback, although The Inquisitr doubted LeBeouf's possible casting.