Cloning lungs was a process that was incredibly expensive, pushing the pair to go after a bounty for the Rebel Alliance. The Rebels paid well for Imperial Governor Nardix, but not well enough. It was at this point that he and 4-LOM were summoned to Darth Vader's flagship, the Executor. Unsure if they were being called to their death for the Rebel bounty they'd captured or not, Zuckuss meditated and used the Gand talent for intuition that's not too unlike the Force. He discerned that Vader did know about their recent hunt, but didn't care. This meeting was regarding something else.When they came out of Hyperspace, Zuckuss and 4-LOM were shocked to see they'd done so in the middle of a space battle. Rebel transports were escaping from the ice planet Hoth, with a fleet of Star Destroyers attemping to capture. The Rebels had a large ion cannon they were using to cripple the Destroyers though, effectively providing cover for the escaping transports. To win some favor with the Empire, Zuckuss decided to fire on one of the transports, taking out its engines. They notified the Executor about what they'd done, and then docked in the landing bay. Zuckuss had to inject pain killers for his lungs, as now was not the time to show any weakness.Vader described who and how he wanted captured. The Millenium Falcon, one of Jabba The Hutt's largest bounties at present as well. Han Solo was meant to be taken alive, and of course there was certainly a way to get both the Imperial and the Hutt bounty on this man and his ship. They may well have a way of paying for those lungs yet.
As they debarked in Zuckuss's ship The Mist Hunter, they decided to take a new look at the Rebel ship they'd stopped on their way in. If they could capture some of the Rebels on board, they could use them to infiltrate the Alliance at the rendevous. Not only that, but if they picked the Rebels with the highest prices on their heads, they could turn them over to the Empire when all was said and done. They docked with the ship, swearing to offer assistance. Once onboard, 4-LOM began scanning the passengers, and called out the ones they could use. After a lot of back and forth, Rebel agent Toryn Farr seemed to convince Zuckuss that the best way to help them would be to release the ammonia in his ship, flood it with oxygen, and thus take on the entire ship's complement. He agreed only to get this show on the road.
The journey to the rendevous proved interesting. 4-LOM decided to assist his companion by learning intuition on his own, but Zuckuss took this as a sign that his partner was preparing to abandon him due to his failing health. Farr also insisted they drop their wounded off at a secret base on Darlyn Boda. Since Zuckuss was wearing his suit this entire time, his lungs were deteriorating even more rapidly. 4-LOM tried to prove his loyaly with the sincerely caring action of letting Zuckuss sleep with a jewel that had healing properties.Once they arrived at the rendevous, the pair had inadvertantly switched sides. Solo was in the hands of fellow hunter Boba Fett. The Rebels were able to grow Zuckuss a new pair of lungs. He and 4-LOM concluded that they could make up for everything if they could capture Luke Skywalker and Leia Organa and turn them over to the Empire, but Zuckuss foresaw that they'd only be able to capture the droids C-3PO and R2-D2. This would do nothing for erasing their current death mark. Zuckuss wanted to stay with the Rebellion. They now had a home, and people who genuinely cared for them. And a cause. 4-Lom concurred.