The 8th novel in this new series. For thousands of years the Earth has been under observation by a race of extraterrestrials. Ten years ago contention among the aliens caused a meteor-like probe to make contact with Tom Swift and Tom Swift Jr. The probe's covert function was to help the aliens determine on how best to deal with what they felt was the problematical expanding intelligence among humans. A few years later, in Ecuador, Sandra Swift encounters a second alien probe. It destroys itself, but not before subtly reprogramming part of Sandy's brain, making her an unwitting spy for the "Space Friends". Now the Sun itself is undergoing a change. Self-replicating machines are forming a shell which, if unchecked, will eventually enclose the star that gives life to our world. And Sandy realizes that the events which began in Ecuador are reaching a terrible conclusion. The Space Friends... up to now aloof and mysterious... are making their presence increasingly known. It's the first note in a vast closing act, and Sandy soon comes to understand that the future of seven billion people depend on how willing she is to put her life on the line.