Ice Age: Collision Course

After the events of the previous film, Peaches gets engaged to a benign mammoth named Julian, whom Manny disapproves of as he finds Julian annoying and incapable of protecting her. The concern escalates when Peaches reveals her wish to travel and explore the world for their honeymoon, which both Manny and Ellie oppose. Diego and Shira want to have children but worry they will not make friends, as the other kids are scared of their species. Sid is about to propose marriage to his girlfriend, Francine, but is dumped by her and laments his solitude.
During Manny and Ellie's wedding anniversary, asteroids incited by Scrat impact and the herd barely escapes to shelter in a cave. Meanwhile, in the underground lost world, following his encounter with a trio of flying Dakotaraptors led by Gavin, Buck discovers an ancient stone pillar and takes it to the surface, where he reunites with the herd. Buck explains that according to the pillar, asteroids have caused two extinctions in the past and, with the next one incoming, he believes that the only place they could find a clue to stop it is on the previous site: a nearby volcano, as according to its engravings, they always fall in that same location.
Gavin and his kids overhear the conversation and decide to stop them, surmising they can avoid the impact by flying away, thus not only exacting retribution against Buck but also eradicating Earth's population and securing domination over the planet for themselves. Roger, the son, is reluctant, but is strong-armed into cooperating. During the herd's journey to the crash site, Buck discovers that asteroids have electromagnetic properties. He theorizes that if a large number of lesser asteroids were gathered and launched into orbit, they could attract the main asteroid away from Earth.
After facing several obstacles and an unexpected encounter with Gavin’s trio, the herd arrives at Geotopia, a community of long-living animals formed inside one of the asteroids that fell long ago. There, Sid meets Brooke, a ground sloth who instantly falls in love with him. Shangri Llama, the leader of Geotopia, ignorantly refuses to cooperate with Buck's plan to use the city's crystals to stop the asteroid, as they are the key to the residents' longevity. Sid inadvertently destroys the entire city when he attempts to remove one of the crystals to give Brooke, reducing the Geotopians to their true age, much to Shangri Llama's annoyance.
After Brooke convinces the other Geotopians that stopping the asteroid is more critical than their lost youth, they and the herd fill up a volcano with a massive quantity of crystals so that the pressure launches them into space to draw the asteroid away. Gavin and his trio attempt to intervene but discover they will not survive the asteroid's impact. Buck convinces them to help, knowing that dinosaurs can co-exist with the mammals. After a lesser asteroid blocks the last and biggest crystal's installation, Julian helps Manny push in the crystal, earning Manny's approval. The volcano erupts, sending the magnetic crystal shards into the sky and repelling the asteroid away from Earth.
The herd departs for home, including Sid, who parts ways with Brooke. Just as they leave, a small crystal shard falls into a hot spring, giving it rejuvenating properties that allow the Geotopians and Granny, who stayed behind with them, to regain their youth. After the herd returns, Manny and Ellie reconcile with Peaches, encouraging her to chase her dreams. Peaches and Julian marry afterwards, while Diego and Shira become heroes to the kids and a rejuvenated Brooke appears during the wedding ceremony to reunite with Sid, much to his delight.