Star Wars’ most fun character delivers one of its most fun films. Until he stops.

Solo: A Star Wars Story the troubled film now directed by Ron Howard and previously by Phil Lord and Christopher Miller finally hits screens in wide release this weekend. Its classic heist movie format and great supporting characters make it a very fun entry in the ancillary Star Wars universe until it stops being fun.

Han Solo (Alden Ehrenreich) is a young scumrat on the shipbuilding planet of Corellia. Along with his girlfriend Qi’ra (Emilia Clarke), Solo survives by running small-time scams for local criminals for just enough money to scrape by. When he pockets a cell of hyperfuel, he and Qi’ra finally have something of enough value to bribe their way off the planet and make a new life for themselves elsewhere in the galaxy. Their plan hits a snag when a gangleader whom Solo owes a debt comes looking for them, causing Qi’ra to get captured and leaving Solo to escape the planet by himself.

Solo trains as a pilot in the Imperial navy until his impetuous ways see him getting kicked down to infantry. During a battle on a muddy planet he runs into a crew led by Tobias Beckett (Woody Harrelson), a gangster impersonating an Imperial officer in order to set up a big hyperfuel heist. Solo begs to go along with Beckett’s crew and sets off to enter a new life as a smuggler and a scoundrel meeting his eventual partner Chewbacca and intergalactic frenemy Lando Calrissian (Donald Glover) along the way.

Solo‘s quality varies in each of its acts. The first act is rushed as several characters are introduced and ton of exposition is unpacked. It comes out of the gates sprinting a little too quickly and takes awhile to find its footing as the characters and plot establish themselves.

The second act is where the big space heist scenes take place. It brings everything you could possibly want from a space heist. Thrilling spaceflight scenes, big-time action and a non-stop pace that’s purest hour of fun yet in the Star Wars universe. The characters play really well together with the right level of snarky camp-cool to feel like classic Star Wars with a smuggler’s edge.

Then comes the third act that just feels like one 35 minute ending dragging out forever. It’s a shame that such a relentlessly fun movie just kind of washes out in a drawn-out climax that tries to tie this story into the rest of the Star Wars Universe when that is really needless. Solo could stand on its own and deserves to, but is undermined by its ending.

Performances are great from top-to-bottom in this. Ehrenreich is certainly not the movie star Harrison Ford became as he originated this character, but he does a very solid job in making Solo his own. Glover is outrageous fun as Calrissian and Harrelson makes the perfect mentor for the scoundrel smuggler Solo will become. The real standout though is Phoebe Waller-Bridge as Lando’s droid L3-37, the most politically aware droid in the galaxy. She’s tremendous fun and a serious comic foil to the light fun that dominates the film.

When Solo gets going it’s a tremendous ride through the galaxy and everything you could want from either a Star Wars film or a summer blockbuster. Its issue is that once it gets off track, it slows down so much that it nearly trashes all the great fun it had built throughout this incredible ride.

Solo is good until it isn’t, but the good parts are more than enough to forgive the bad.