The original cast of “Back to the Future” has reunited – not for a reboot, but to help locate a piece of movie history that went missing about 40 years ago.

For four decades, a crucial piece of cinematic history has been missing. It’s the iconic cherry red Gibson ES-345 that Marty McFly shredded during the legendary Enchantment Under the Sea dance scene in Back to the Future—an electrifying moment that sparked a generation of guitarists and cemented the instrument’s place in pop culture.

In a story about time travel, anything can happen, but one question remains: whatever happened to the guitar used in a pinnacle scene of “Back to the Future?”