In the year 1997, Professor John Robinson and his family are selected to establish a colony on the third planet in the Alpha Centauri star system as Earth is hugely overpopulated. The scheming Doctor Zachary Smith, an agent from an enemy government, is sent to sabotage the mission, and is successful in reprogramming the ship's robot. However, he gets trapped on the ship and due to the excess weight, the ship becomes hopelessly lost in space. The family's mission, then, becomes a fight for survival as they search for their way home. Features the complete 24 episodes from the third season.