Take Olivia Newton John, Gene Kelly, and Electric Light Orchestra and rollerskating disco and what do you end up with? A wonderful train wreck called Xanadu. Hated by the critics but later made into a hit Broadway musical, I have to admit that this has always been one of my guilty pleasures.
For those who have never seen the movie, here is the plot as described at Wikipedia:
Sonny Malone (Michael Beck) is a talented artist who dreams of fame beyond his job, which is painting larger versions of album covers for record-store window advertisements. As the film opens, Sonny is broke and on the verge of giving up his dream. Having quit his day job to try to make a living as a freelance artist, but having failed to make any money at it, Sonny returns to his old job at AirFlo Records. After some humorous run-ins with his imperious boss and nemesis Simpson, he resumes painting record covers.
At work, Sonny is told to paint an album cover for a group called The Nine Sisters. The cover features a beautiful woman passing in front of an art deco auditorium (the Pan-Pacific). This same woman collided with him earlier that day, kissed him, then roller-skated away, and Malone becomes obsessed with finding her. She finds him and identifies herself as Kira (Olivia Newton-John), but will tell him nothing else about herself. Unbeknownst to Sonny, Kira is one of nine mysterious and beautiful women who literally sprang to life from a local mural near the beach in town.
Sonny befriends a has-been big band orchestra leader-turned-construction mogul named Danny McGuire (Gene Kelly). Danny lost his muse in the 1940s; Sonny has not yet found his muse. Kira encourages the two men to form a partnership and open a nightclub at the old auditorium from the album cover. She falls in love with Sonny, and this presents a problem because she is actually the Olympian Muse of dance, and her real name is Terpsichore. The other eight women from the beginning of the movie are her sisters and fellow goddesses, the Muses, and the mural is actually a portal of sorts and their point of entry to Earth.
As it turns out, the Muses visit Earth often to help inspire others to pursue their dreams and desires. But in Kira's case, she had broken the rules, as she was only meant to inspire Sonny, but ended up falling in love with him as well. Her parents (presumably the Greek gods Zeus and Mnemosyne) recall her to the timeless realm of the gods. Sonny follows through the mural and professes his love for her.
A short debate between Sonny and Zeus occurs with Mnemosyne interceding on Kira and Sonny's behalf. Kira then enters the discussion, saying that the emotions toward Sonny that she has experienced are new to her and asks if they could only have one more night together to let Sonny's dream of Xanadu becoming a success come true. But Zeus ultimately sends Sonny back to Earth. After Kira expresses her own feelings for Sonny in the song Suspended In Time, Zeus and Mnemosyne decide to let Kira go to him for a "moment, or maybe forever" (mortal time confuses them) and the audience is left to wonder her fate.
In the finale of the movie, Kira and the Muses perform for a packed house for Xanadu's grand opening, and after Kira's final song they return to the realm of the gods in spectacular fashion. Sonny is understandably depressed thereafter, but that quickly changes when Danny has one of the waitresses bring Sonny a drink. The waitress appears to be none other than Kira--she's been allowed by Zeus to stay as long as she wishes. Sonny approaches her and says he would just like to talk to her.