Age of Extinction picks up several years after the last entry, 2011’s Transformers: Dark of the Moon. In case you don’t remember, that movie ended with the Autobots victorious in a battle that laid waste to much of Chicago, Optimus Prime intoning that he would always protect Earth and its inhabitants. As it turns out, not so much. The Chicago battle has convinced humanity that all Transformers are bad, and the Autobots have gone into hiding (Optimus was nearly killed at some point, apparently, and hasn’t been seen since). A CIA agent (Kelsey Grammer, talking very deliberately and never blinking) is making a name for himself by hunting down the Autobots and killing them one by one — only he’s telling the president that he’s actually killing Decepticons. Perhaps he’s lying because he’s working with a robot bounty hunter named Lockdown, who is never set up or explained in any meaningful way — but his face does turn into a pretty cool-looking gun.

Meanwhile, Mark Wahlberg plays Cade Yeager, a single dad trying to keep his home out of foreclosure and provide for his 17-year-old daughter, Tessa (Bates Motel’s Nicola Peltz). Cade is an inventor, mainly because he wears glasses and keeps reminding everyone that he’s an inventor, but he’s forced to make ends meet by repairing junk that he salvages. One day he’s picking up scraps from an abandoned movie theater, where he comes across a broken-down semi truck. What follows is such a mess of random events and happenstance that it’s best described in snippets rather than pretending it builds any sort of meaningful narrative: Cade repairs the truck and finds out that it’s Optimus Prime. They team up with the few remaining Autobots, with Grammer’s CIA hit squad in pursuit. Cade and company discover that a mercurial tech executive (Stanley Tucci, the film’s one consistent highlight) has found a way to build Autobot clones using a rare element called "transformium." Tucci sics his clones on our heroes, because the aforementioned robot bounty hunter wants Optimus Prime so badly that he’s willing to give Tucci a device that will create even more transformium in return.

And yes, it’s really called transformium.