In the world of Katherine Marsh’s young adult novel, “The Night Tourist” (Hyperion, 240 pages, $17.99), the answer to the awesome question of what happens when we die can be found in one place: Grand Central Terminal.

“The Night Tourist” is the story of 14-year-old Jack Perdu, who loves classic languages and is as awkward as he is precocious. One day — his head buried in a book — the youngster is hit by a car. After the boy comes home from the hospital, his widower father, a Yale University professor, sends him unaccompanied to see an unconventional doctor in New York City.

But on his way back to New Haven, Jack decides to explore Grand Central Terminal. While there, he meets a mysterious teenage girl named Euri. Jack quickly learns that Euri is a ghost, and she leads him into an underworld; there, the pair embark on a risky adventure to find Jack’s deceased mother.

Filled with references to classics (the underworld is modeled after that of Greek mythology) and to New York City history, “The Night Tourist” will appeal to intellectually curious young adults without alienating the non-history buffs. The author creatively tackles the heavy themes of death and forgiveness, but not at the expense of humor. At one point, Jack asks, “Where is Elysium?” — the paradise where the dead go once they are at peace in both Greek mythology and in Ms. Marsh’s fictional world. Euri responds: “Somewhere in The Hamptons. That’s my guess, anyway.”