Samuel Lap, an 8 year old Amish boy, is on his first trip to the city of Philadelphia with his mother, Rachel (Kelly McGillis). While in a public restroom, Samuel is the sole witness to a murder of a man, who turns out to be a police officer. Detective John Book (Harrison Ford) is assigned to the case. With a little investigation Book realizes that dirty police, involved with drugs, are behind this murder. Book must ensure the witness makes it to court to testify, as the bad guys try to knock both Book and Samuel off. After being wounded, Book decides the best way to stay a live is to hide out in Amish country. Here Book learns to live like the Amish and inevitably falls for Rachel. However, the corrupt cops aren't giving up on their search for Samuel and eventually end up tracking them all down.