A cowardly alien race known as the Boov finds near-future Earth a suitable place to call “home”. Led by Captain Smek (Steve Martin), they commence their “friendly” invasion of the planet, relocating the humans, whom the Boov deem as simple and backwards, to remote parts of the planet while the Boov inhabit their homes in a quick and bloodless conquest. One of the Boov, named Oh (Jim Parsons), is a more excitable, freethinking member of the species, who decides to invite the Boov to his apartment for a housewarming party, despite the race’s antipathy towards him. Not far from Oh is a 14-year-old girl named Gratuity “Tip” Tucci (Rihanna), who drives away through her home city to find her mother Lucy (Jennifer Lopez) after being separated from her during the invasion, leaving her with only her Japanese Bobtail Pig and fueling her hatred for the Boov.
Oh runs into the street to meet up with a grumpy Boov cop named Kyle (Matt Jones), who, like the rest of the Boov, doesn’t want to befriend him. Oh invites him to the party and accidentally sends a mass invitation to every Boov on Earth. However, the “send all” button he pressed actually sends the invitation to every alien race in the entire galaxy, including the Boov’s enemy, the so-called planet-destroying Gorg (Brian Stepanek), whom the Boov have been running from since a failed peace treaty between the Gorg and Captain Smek resulted in Smek running away with “The Shusher” (a possession of the Gorg’s), which is used as a means to showcase leadership amongst the Boov. Everyone, aggravated with Oh for compromising their new home to their enemy, starts chasing him down. Oh runs into a convenience store to hide just as Tip and Pig enter the same store to grab supplies. They come across each other in a hostile manner, and after Tip’s car fails to start, Oh transforms it into a fantastical, hovering craft named Slushious to continue transportation. Oh hitches a ride with Tip when he promises to help her find Lucy, but unfortunately, they must go to the Boov Command Center in Paris and locate her from there. However, Oh secretly plans on abandoning Tip to take himself to Antarctica, the only place on Earth un-infested with Boov, although he fails in doing so after Kyle attempts to gain his personal password so the Boov can hack into Oh’s account and cancel the invite.
After reaching the Boov Command Center, which is in the now-floating Eiffel Tower, Oh manages to get into his account, and deletes the message with just a second to spare before it reaches the Gorg. He then plugs in Tip’s brain to help her find Lucy. They eventually trace her location to Australia, where she is also looking for her daughter. The other Boov then find the two and try to “erase” Oh, while Tip grabs the gravity manipulation system and flips it over, causing the whole Tower to tilt upside down, hence the two manage to escape. As time goes on, Oh and Tip gradually become friends, and Oh slowly realizes how flawed the Boov’s perspective on the invasion actually was.
As Oh and Tip head off to Australia, they are ambushed by other Boov riding by them in fear, and realize that a fleet of Gorg ships is close behind them. Tip and Oh manage to knock one down, but in the process a chunk of it hits them and they lose their slushie fuel, causing the car to crash-land. They come across the fallen Gorg ship and find out that it is actually a drone. Oh recovers a special chip and uses it to get their car up and running.
Tip and Oh make it to Australia and see the Boov evacuating to their mothership. When they land the car, Tip immediately starts looking for her mother, but Oh insists on him and Tip evacuating with the other Boov instead. Angered at Oh for attempting to break his promise again, Tip declares that he wasn’t truly her friend in the first place and abandons a depressed Oh, who retreats to the ship. The Gorg mothership comes close to the Boov ship, but Oh pulls out the Gorg chip and uses it to fly the ship further away from the Gorg. The Boov become astonished at Oh’s bravery, but Smek becomes upset and reminds everyone that he is the captain. However, Oh stands up to Smek, telling him that he’s a terrible captain and tells the Boov about what he learned from Tip about humans caring for other people while the Boov do not. Saddened by this revelation at first, the Boov then mutiny against Smek and Kyle grabs Smek’s “Shusher”, handing it over to Oh and declares him their new captain, although Oh is ultimately depressed and unsatisfied that he left Tip behind on Earth.
Tip rushes aimlessly around the city to find Lucy, but in vain. She fruitlessly tries to show everyone the picture of Lucy on her phone, but no one can help her before the phone’s battery dies and Tip is now tearful, so she gives up and sits in the empty Ask A Boovbooth and bursts in tears. Oh returns to her side and helps her track down Lucy. The mother and daughter finally reunite and thank Oh. Suddenly, the Gorg mothership descends upon the planet, and Oh realizes that they want the rock on the Shusher. Oh runs to the ship to try to attract its attention, locking Tip and Lucy in the car for safety. Tip breaks out of the car and shines a light in the Gorg Commander’s face to bring his attention to Oh as he holds the rock up. The Gorg Commander halts the ship as it crunches down on the ground, with Oh directly in its path. Tip rushes to rescue him, but Oh is seemingly crushed beneath the ship until it backs up and reveals him uninjured. The Gorg Commander emerges from his armor to show that he is actually a harmless starfish-like creature. Oh returns the rock to him, which turns out to be an egg for millions of developing Gorg larvae; the next generation of Gorg, revealing that the Gorg Commander/”Father” had been the last of his kind, alone and almost extinct, hence why he pursued the Boov so fervently. He thanks Oh and departs.
Two weeks later, the humans have returned to their original homes, and Oh finally gets to have his party at his apartment, with both humans and Boov in attendance. Tip plays her music and gets the rest of the Boov to experience dancing for the first time, while other Boov, including a reformed Smek, party on the moon, and several ships from other planets, including the Gorg and his babies, head to Earth for Oh’s party upon receiving his invitation.
It is a cute movie but also forgettable when it comes to plot. Kids do love it though.