Video begins with a gang of Montagues arguing, Mercutio among them; all dialog is in Hungarian and there are no subtitles. A voice from elsewhere shouts to them; it’s Tybalt. Mercutio announces anticipatorily, Capulets! Tybalt says he’s looking for Romeo, and is promptly harrassed as though this has a double-meaning. The song begins when Tybalt loses his temper, and Mercutio and Tybalt begin harrassing each other. Romeo eventually joins the scene and he and Benvolio try to break up the fight.
Right before the moment in which Tybalt runs at Romeo and Mercutio with his knife drawn, in the last lines of song, Mercutio runs his hand intimately through Tybalt’s hair, which utterly infuriates him.
Tybalt rushes in to stab Romeo, and appears to have stabbed Mercutio entirely by accident; he is clearly devastated, and runs off. Mercutio collapses, and the rest of the video is his death song and Romeo’s grief.
For me the queerest part is the moment when Mercutio touches Tybalt’s hair. The line in Hungarian is:
Both: Színház az élet!
Tybalt is saying, “Life is not a theater!” and Mercutio is saying, “Life is a beautiful theater!” Because of the way Hungarian words, the word for negations is the same word for “no”—so in the scene this has a double meaning: Mercutio touches Tybalt’s hair and coyly sings “beautiful” while Tybalt shouts “no!”
Earlier in the scene, before the song has begun, when Mercutio begins goading him, he calls Tybalt “szép”. This is a Mercutio who earlier in the show kisses Romeo, though what he means by it isn’t all that clear.