Plot

Op and Ed accidentally time-travel from the Galapagos Islands in 1835 to present-day Shanghai. They make their way through the city in confusion and make the horrifying discovery that the species to which they belong became extinct shortly after.

When two Flummels (an adorable species of fluffy animals with holes in their center) are magically transported to the present day, they learn that their species are now extinct and forgotten. They must now travel back in time to try to save their race from disappearing forever.

Op and Ed accidentally time-travel from the Galapagos Islands in 1835 to present-day Shanghai. They make their way through the city in confusion and make the horrifying discovery that the species to which they belong became extinct shortly after.—Sky Cinema

At the Galapagos in 1835, Op tries to convince the flumes about everything that she's been through. She's discovered they are all in danger from the island volcano that is about to swallow them. But there's a surprise for Op, Ed and the others when they learn the true reason flumes went extinct. All hope seems lost as our tiny flannel heroes must try to save their entire species all by themselves.—Netflix

The story involves an adorable species of fluffy animals, called "Flummels". When two flummels are transported into the present day, they learn that their species has become extinct, and they must travel back in time to try to save their race.

In 1835, Charles Darwin has set sail for the Galapagos Islands.

Brother and sister, Op (Rachel Bloom) and Ed (Adam DeVine) are Flummels-fluffy rabbit-like creatures with holes in their center who are native to the Galapagos islands. The Flummels travel by rotating around their round bodies like a tire. The pair are ostracized by their community due to Op's proneness to disaster. The community is led by Mali (Alex Borstein), a female brown Flummel & Jepson (Henry Winkler), a large, Grey male Flummel. It is the 100th Flower Festival and the community has created a giant flower Flummel and they will carry it to the top of a mountain for festive celebrations. As Op and Ed continue to attract disasters, Jepson sends them away to the beach, away from the festive celebrations.

Op attracts Wally (Richard Kind), a talkative blue whale to the beach with her waving motion. Op and Ed try to shoo Wally away, but the waving motion and the shooing motion are no different and Wally thinks that he is being invited to the beach for a conversation. Wally brings in a tidal wave along with it, that washes away the 100th flower festival celebrations of the Flummels and adds to the list of disasters with Op. Due to this, Jepson banishes Op and Ed from flower festival and asks them to serve time on desolation rock.

Op and Ed decide to find new exotic flowers on the mountain to make up for their mistake in wiping out the flower festival. Op finds a large attractive flower on the edge of a cliff. She works with Ed to rappel down the edge to access the flower. Just before Charles Darwin (Tom Hollander) discovers their island during one of his voyages, Op and Ed find and fall into a large flower that Teleports them to modern-day Shanghai (inside a normal civilian home, which had the same flower in it), where they meet and befriend a poodle named Clarance (Ken Jeong). Clarance is not able to explain the concept of time travel to the Flummels and takes them to the museum of natural history for a visual aid. The siblings learn (at the museum of natural history) their species is now extinct after Darwin found the island destroyed by a volcanic eruption. Only a small part of the beach survived, where Darwin found some Flummel fossils which indicated the existence of a living species on the Island.

Clarance brings them to the Time Terminal, a pavilion where Clarance's owner Dr. Chung (Benedict Wong) kept and studied the flowers and their seeds, which have time traveling properties. Each seeds maps to a location and a point in time. At the time terminal one could choose which time period one wants to travel through by putting the relevant seed in the Terminal. Though, Dr. Chung himself got lost travelling through time. Op plans to travel back to the Island, before the volcanic explosion, and warn everyone about the impending disaster. Ed is skeptical as Flummels do not trust Op and Ed and are not likely to believe them. Op accidentally knocks some seeds out, causing the Terminal to malfunction and sending Clarance to 1915 Antarctica along with the seed that leads to the Flummels home. In Antarctica, Clarance is captured by Ernest Shackleton's expedition team.

Op and Ed find the Extinctables-a team of extinct animals composed of Dottie (Zazie Beetz), a dodo; Burnie (Jim Jefferies), a Tasmanian tiger; Alma (Catherine O'Hara), a Macrauchenia; and Hoss (Reggie Watts), a Triceratops, who were bought by Dr. Chung to the Time Terminal. The Extinctables say that at the Time Terminal, time stands still and hence they are safe. They prefer not to go back to their time or any other time as time only brings unknown dangers which only leads to death and destruction

Op and Ed travel through each seed (Cupertino, Oliver Wright, Cleopatra, Titanic and so on. they have no other option as the seeds were displaced from their cases, which indicated their location and time) in order to find the one that can bring them home and rescue Clarance. Op and Ed learn that time arcs from 2 flowers creates a vortex that disassembles the molecules of any object in the vortex and reassembles it at a randomly different point in time.

Ed is angry with Op for getting everybody in danger and decides not to accompany her. Op goes back to her time alone, where Mali and Jepson refuse to believe her and ask her to leave the flower festival. Ed realizes that his life is empty without Op and decides to follow her.

Op then returns to the Flummels' time, where Op and Ed attempt to warn the rest of the Flummels about the volcano. Clarance imprisons Op, telling her that Flummels ruined his life (as they were the most popular pet, and nobody wanted dogs anymore) and that he is actually behind their extinction. Clarance had been adopted by Dr. Chung (as he wanted to experiment time travel with a pet first), but after Dr. Chung was charmed by the adorable Flummels, Clarance became jealous, pushing Dr. Chung into one of the flowers and destroying the seed that would bring him back.

He then caused the Flummels' extinction by planting a drone bomb. Meanwhile back in the time terminal, the Extinctables find a video of Dr Chung saying that he was travelling to 1417, and also find evidence of Clarance pushing Chung into the portal and destroying the seed. Dottie devises a plan to travel to 1418 (where there is another time flower), to rescue Chung and bring him back. Op and Ed make several attempts to escape and stop the bomb. They free the Flummels after defeating the Cyclops sent by Clarance and use Chinese firecrackers to attract Darwin's attention and come to the beach to rescue them. But the firecrackers end up on the ship, burning it down. They eventually deploy 2 flowers to create a vortex and to move the entire island into the present day. Clarance survives, but Dr. Chung arrives and takes him, thanking the Flummels and the Extinctables.

Sometime later, Op and Ed are finally accepted by their community, while Dottie surprises Ed by laying an egg shaped like a Flummel. The egg hatches, but the creature inside the egg is unknown.