Episode IV or VII

Starts with imperial raid which involves major leader on rebels. A rebel leader is captured, but a critical secret message is jettisoned inside a droid onto a desert planet. After a short while, the droid is rescued from some small scavenging creature by a young person which coincidentially is very strong in the force. The youth and the droid escape the desert planet onboard the Millenium Falcon after a short skirmish with some stormtroopers. In transporting the droid, they see the baddies used their weapon to destroy a planet. The group find themselves on the giant weapon, they sneak around and disable some key defensive components and also rescue the girl imprisoned on the death ball. As they begin to leave, the older man who was once the bad guy's mentor confronts the bad guy, and is killed. The rebels attack the death ball with inside information they acquired in relation to the droid's rescue, led by a youth we initially met on the desert planet. Right before the death ball can fire its weapon again, the rebels succeed in taking it out, despite taking heavy losses...