The Sparta P.D. investigates a series of big truck accidents that seem to have a common element to them. When the last driver of the fourth truck crash is autopsied, he is found to have speed in his system. Meanwhile, Althea is worried about one of her students, Shelley Hughes, when she tells about her miserable home life and that her mother's boyfriend Bobby Foster is primarily the one to blame. Althea frustrates Virgil when she vows not to let Shelley be questioned by the police and also doesn't tell Virgil pertinent information involving this case. The Sparta P.D. must work quickly to uncover who is pushing the illegal drugs to these big rig drivers.