Kirk and Monty have known each other since they were boys in London. Now, feeling the impending doom of middle age, the two of them decide to set out on The Mongol Rally, an over 4,000-mile charity car chase. Knowing that the people in charge of the rally prefer small, comical vehicles, the two of them buy a scooter and an old BMW Isetta. With no set route, they set out across Europe, looking for adventure and meaning in their lives. Along the way, they run into fellow rally goers, including making friends with an American named Donkey who fancies himself a steampunk airship captain.

As Kirk and Monty continue their journey, they meet new and interesting people, get lost, lose their vehicles, and begin to feel strange things about one another. The rally changes their lives forever, but will Kirk and Monty’s budding romance survive once they get back to the real world?