Old grudges die hard in the new full-length trailer for "Cobra Kai," the sequel to "Karate Kid."

The YouTube Red series brings back former teen enemies Daniel LaRusso (Ralph Macchio) and Johnny Lawrence (William Zabka) many years after their infamous martial arts battle. Now, they're older, though maybe not wiser.

Daniel is a successful car dealership owner, while Johnny is down and out. But after Johnny helps a teen boy (Xolo Maridueña) fend off some bullies, he finds himself reopening his old karate dojo and teaching a misfit group of pupils his style of karate. That doesn't sit well with Daniel, who vows to shut it down. "Not on my watch," he says of Cobra Kai's revival.

The series seems to flip the two men's roles. Where once Daniel was the underdog, now Johnny is the one scrapping against someone more powerful. And the former bully is now the one combatting the bullies.

"Cobra Kai" premieres May 2 on YouTube Red.