Fitz and Simmons finally got married on “Marvel’s Agents of S.H.I.E.L.D.,” but don’t expect them to go on a honeymoon. The wanted fugitives are still searching for a way to save Coulson and stop the end of the world on the ABC drama.

“The team goes in search of Gravitonium in order to help save the world,” the Season 5, episode 13 synopsis teases.

Fitz (Iain De Caestecker) used Gravitonium from Deke’s (Jeff Ward) belt buckle to help seal the crack in the Lighthouse last week. Was it only a temporary fix? Or is something else causing the end of the world?

The title of this episode is “Principia,” and that could be another hint. The word often refers to Philosophiæ Naturalis Principia Mathematica, Isaac Newton’s work about the laws of motion and universal gravitation. It seems like this is definitely something Fitz and Simmons (Elizabeth Henstridge) have read.

This week’s “Agents of S.H.I.E.L.D.” will also pick up the episode 11 cliffhanger. General Hale (Catherine Dent) recruited Carl “Crusher” Creel (Brian Patrick Wade), a.k.a. The Absorbing Man. He’ll show up again in this episode, and we’ll likely get more details about what exactly Hale want him to do.

When we last saw him, it was clear that he and Hale had already met. The government agent was looking for him because S.H.I.E.L.D. resurfaced. Creel didn’t seem particularly happy to work with her, but he couldn’t resist getting in her car once she said she was putting together a team.

Could a different villain from previous seasons be on that team? Another blast from the past will come with Werner Von Strucker’s (Spencer Treat Clark) return. The son of Wolfgang Von Strucker was a big part of “Agents of S.H.I.E.L.D.” Season 3 when the agents were fighting Hydra, but he was last seen in a coma.

This episode is full of interesting guest stars. Katie Amanda Keane is listed as playing Deke’s mom, so a flashback seems likely.

Also expected to appear is Ruby (Dove Cameron), Hale’s killer daughter who sliced off Yo-Yo’s (Natalia Cordova-Buckley) arms. If she sees the team again, it’s safe to say that there will be a nasty fight. The team isn’t going to take their friend’s injury lightly.

With so much going on, we have to wonder when the team will find time to save Coulson (Clark Gregg). The leader revealed last week that he is dying after making his deal with Ghost Rider, and the agents surely aren’t going to just accept that. The promo video makes it clear that they are fighting for Coulson.

“Marvel’s Agents of S.H.I.E.L.D.” Season 5, episode 13 airs Friday at 9 p.m. EST on ABC.