In Chicago, a secret L train runs through the mythical East Side of the city. On that train, you'll find a house-cat conductor, an alcoholic elf, a queen of the last city farm, the most curious wind, and an exceptional girl by the name of Francesca Finnegan.

When we first encounter Richard K. Lyons, he is a man who has long forgotten the one night, when he was still a boy called Rich, when Francesca invited him aboard the secret L for an adventure through the East Side. The night was a mad epic, complete with gravity-defying first kisses, mermaid overdoses, and princess rescues. Unfortunately for Rich, the night ended like one of those elusive dreams forgotten the moment you wake. Now, Rich is all grown up and out of childish adventures, an adult whose life is on the verge of ruin. It will take the rediscovery of his exploits with Francesca, and a reacquaintance with the boy he once was, to save him.