Eleven-year-old Ursula Neilsen didn't believe NASA's verdict that carelessness killed her older sister Andrea, an astronaut on a routine mission to repair a crippled satellite. But there wasn't much a kid could do about it. Years later, "Bear" finds herself the target of someone who's trying to kill her because she knows too much. Seeking help from a disgruntled former NASA engineer, she learns that the space agency conducted an illegal experiment on her sister an may now be covering up the presence of an alien Andrea made contact with. The deadly puzzle inspires Bear to go into space to vindicate her sister, a decision that seems about to cost her her life.