Rab has been diagnosed with Asperger's Syndrome, and for his twenty seven year old son, Ben, it explains all his dad's quirks - the shouting at the television, the intense hatred of certain types of fabric, the obsession with black biros, and his refusal to allow his son a surprise party "with people".

But whilst Ben resolves to help his dad in any way he can, Rab has other ideas. He reckons it is Ben who needs help, and organises therapy for him as well as going against the grain by planning an amazing party for Ben's upcoming birthday.

With the assistance of Tam his "bigoted friend", Rab challenges his Asperger's to make sure that it is the best surprise party ever, complete with "people".