After the battle of Hoth, the remains of the rebel fleet separated into and escaped to the outer rim. One of the groups accidentally ended up in the Saasquaan system. The empire had been watching closely the civil war raging for years between the saasquaans after the end of the Clone Wars, waiting for the right moment to intervene. The reason? Kyber crystals. The Jedi Order always considered Saasquaan to be a prominent spot for kyber crystal extraction, as well as a religious pilgrimage site during the times of The Old Republic. Now, the Galactic Empire wants those valuable crystals to power the Second Death Star, under construction in the neighboring Endor system.