Instant New York Times Bestseller The bestselling author of Wonder returns with an unforgettable adventure about a boy on a quest to rescue his father, with only a ghost as his companion and a mysterious pony as his guide. When Silas Bird wakes in the dead of night, he watches powerlessly as three strangers take his father away. Silas is left shaken, scared, and alone, except for the presence of his companion, Mittenwool . . . who happens to be a ghost. But then a mysterious pony shows up at his door, and Silas knows what he has to do. So begins a perilous journey to find his father--a journey that will connect him with his past, his future, and the unknowable world around him. R. J. Palacio spins a powerful and heartwarming story, one of those rare books destined to become a classic, beloved for generations to come.