From the introduction: Long ago in a galaxy far, far away A trans-reality comet hit the Galra homeworld, creating a tear to the Quintessence Field, a realm of pure energy. Unfortunately, this ticked off the energy beings that lived within the field, leading to them invading this reality. To combat this threat, King Alfor of Altea used the trans-reality comet to create the five Voltron lions. Working together, the five paladins and their lions were able to beat back the threat and seal the rift...but not without cost. The Galra homeworld was rendered uninhabitable.