To widower Joe Cramer, his only mission is to provide care and a cure for his ill daughter, Cindy. Paired with Mona Watson, they mine Saturn's rings for radioactive boulders, plunge into the ocean beneath Europa's crust in search of blind fish and dive into Jupiter's atmosphere to learn the secret of The Great Red Spot.

While Witherspoon, the solar system's tycoon, pays them well, he has his own agenda. He plans to send Cramer and Mona on the most dangerous mission of all: a trip to the star, Sirius.

Cramer wants to refuse. Exceeding the speed of light isn't possible, so the trip will take several years. To complicate things he discovers he has feelings for Mona that need to be ignored to complete the mission and return home. Will Cramer ever see his daughter again?