Sherlock Holmes' problem with disturbing dreams proves to be both an impediment and an aid in the search for a missing woman.
The story begins on a small spaceship docking with a refueling station. On board are a group of four aliens, Bernard, Sandra, Desmond, and Julian. During a particularly tedious period of their stay at the station, the other three begin playing with the ship’s controls while Bernard is outside playing spaceball. They accidentally disconnect his part of the ship, leaving him stranded while they crash into a large blue planet close by (Earth).
Along with his new friends, a teenager who was arrested by the US Secret Service and banned from using a computer for writing a computer virus discovers a plot by a nefarious hacker, but they must use their computer skills to find the evidence while being pursued by the Secret Service and the evil computer genius behind the virus.
American heiress Henrietta Doran (known as Hatty) marries Lord St Simon, but she vanishes without trace on her wedding day, leaving London agog. Later, the police find her wedding dress in the Serpentine, a lake in a London park, with a note in the pocket of the dress. While investigating the case, Holmes suffers from nightmares, which he sees as a factor in the mystery.