Champion, a beautiful show-horse, dies mysteriously in a pasture, and the Critter Gitters team is called in to investigate. As Dr. John West and his partner, Dr. Kaitlin Melling explore the causes, another case springs the Critter Gitters into action. Bobby and Susan answers a call from a frightened youngster who has discovered what seems to be a rattlesnake in the kitchen. The coiled snake has the girl’s mother and brother cornered and is ready to strike! The Critter Gitters rush to the scene to rescue the family. Meanwhile, Professor Headful is furiously working in the Critter Gitters laboratory preparing for the Critter Gitters expedition to Costa Rica to track down and capture a terrorizing creature know as the Chupacabra! Tension builds back at the clinic as another horse collapses in the valley and the team tries to solve the mystery of the dying horses.