Sit, Rover, Sit! Eagle, Robyn and Hawk are sent to retrieve three old rovers from Mars, for reassignment to new jobs on Earth. Robyn locates Curiosity and finds that she relates to the no-nonsense robot, whose attention to detail rivals her own. Hawk finds Opportunity, and is immediately fond of the chatty rover. Meanwhile, Eagle locates Spirit buried in a sand pile. As he unearths the damaged robot, he unexpectedly finds himself assisted by a small rover mutt, who helps him to dig. But who is he, and what is his purpose? The little rover trails after him like a faithful pet... so Eagle names him Rover and brings him home. At Stardust Bay, Curiosity and Opportunity are prepared for their new assignments, but Eagle's pet Rover's fate is uncertain. It's only once Spirit is repaired that the truth emerges: the little Rover is Spirit's assistant!