Gaspery is the central character in Sea of Tranquility. Mandel only uses the first person for his character, and he appears—as a time traveler—in all sections of the novel. Gaspery uses several disguises while time-traveling, including masquerading as a priest and claiming to be a journalist. A consistent clue to his use of facades is the motif of his accent being “off.” Mirella notes that he “seemed foreign in a way that she couldn’t quite parse” (49). His identity as a time traveler is hinted at but not fully revealed until the book reaches his time, 2401, in Part 4. At the end of the novel, Gaspery surgically changes his appearance and becomes Alan, the violinist, and triggers the anomaly—where moments in time bleed into one another.

He grew up in Night City, the second moon colony, near Olive’s house (200 years after her), and was named after a character in her book. He is initially listless and directionless. After he moves to Colony One, his sister (Zoey) tells him about the anomaly, and he becomes passionate about working for the Time Institute. Gaspery says, “[I]t’s the most interested I’ve been about anything in maybe my entire life” (138). However, after meeting Olive, he finds he cannot abide by the rules of the Time Institute and saves her life by telling her about her future.