After implying he'd like to "flex new muscles" after Transformers 4, director Michael Bay has officially passed on helming Transformers 5 -- and instead, will tackle the Benghazi-based 13 hours. According to Variety, Bay's 13 hours is based on the novel Thirteen Hours: A Firsthand Account of What Really Happened in Benghazi by Mitchell Zuckoff, which had its film rights acquired by Paramount in February.