The Van is the story of two friends, Jimmy Rabbitte, Sr. and Bimbo Reeves, who operate a chipper van on the outskirts of Dublin. Bimbo uses money he got when he was laid off from his job to buy the van and he invites his buddy, Jimmy Sr. to be his partner. They work very hard to get the van cleaned up and working. With the help (or leadership) of Maggie Reeves, Bimbo's wife, they work out their menu, which is basically fish and chips, burgers, and sausages, and, with the help of Veronica Rabbitte, Jimmy Sr.'s wife, learn how to cook it. They open and begin to catch on very well, but Jimmy Sr. soon feels that Bimbo and Maggie are making all the decisions and not listening to him. The friendship begins to falter, then goes completely off the rails. After one final and thoroughly nasty fight, Bimbo drives the van into the Irish Sea.

The book begins by introducing Jimmy Sr. and his family, and shows how he spends his days. Until Bimbo is laid off, Jimmy Sr. spends his days aimlessly visiting the library or playing Pitch and Putt golf. He is lonely and a little scared. After Bimbo is laid off, Jimmy Sr. at least has someone to hang out with. Bimbo is more ambitious and wants to find a new job, or something to do that would be more productive than just doing nothing. He notices that a chipper van that used to be outside their favorite pub, The Hikers, is no longer there. That gives him the idea of running a van. He tells their friend Bertie about it, and Bertie finds one that is available. Bimbo buys it and asks Jimmy Sr. to be his partner. They shake on it.

Through a lot of hard work they get the van ready to open for business. They tow it to The Hikers (the van has no engine), and right from the first night they begin doing good business. Bimbo's wife, Maggie, is an active participant. She keeps the books, helps them plan what to serve, finds out how to buy it, and gets them a license for a spot by a beach near where they live. Gradually, Jimmy Sr. begins to resent Maggie's involvement. When Bimbo tells Jimmy Sr. he is going to be paid a weekly wage, Jimmy really starts acting out. He purposely does things he knows will annoy Bimbo, and pushes him to the point where they begin to have serious fights.

After one such fight Jimmy Sr. says he is quitting and storms out of the van. Bimbo chases after him and begs him to come have a couple of pints. That is an invitation that Jimmy Sr. can never refuse, but he does continue to resist Bimbo's pleadings. Bimbo even offers to make Jimmy a partner and share everything fifty-fifty, but Jimmy Sr. will not take his hand. Finally, Bimbo, who by this time is pretty drunk from several rounds of pints, says he is going to kill the van. Taking Jimmy Sr. with him, Bimbo drives out to the beach and drives the van into the water until it will not go any farther.

Jimmy tries to pull Bimbo back out of the water, but Bimbo wants to keep watching the van. Jimmy Sr. walks home alone.