Wallace accidentally discovers a cure for Covid after eating some mouldy cheese, works to synthesise a vaccine from this with the help of a generous scientific benefactor who turns out to be Feather’s McGraw intending to sell the vaccine on the black market at an extortionate rate.
Gromit eventually alerts an oblivious Wallace to this who races to the lab in his wrong trousers, losing control and smashing every vial but one in the hands of Feathers who is chased by Gromit through a series of conveyor belts. Feathers finally drops the vial which smashes on the ground but the liquid inside pools into the shape of the moon giving Wallace an idea.
W&G dust off their rocket ship and head back to the moon to farm the right cheese and have an emotional reunion with the skiing cooker robot. On the way back to earth skiing cooker robot falls apart from years of neglect but Gromit rebuilds him into a cheese-vaccine dispensing machine saving the human race.