Neptune's Angel

Just when C. A. T. thinks Triton Base is back to normal, an inbound cargo craft radios a mayday. Seems a computer virus has infected the controls, and the ship is on a crash course toward the liquid oxygen fuel depot, a collision that will destroy the base in a fiery inferno. While Commander Zacman and his crew try everything they know to avert disaster, C. A. T. investigates and discovers this virus is its old nemesis from back on Callisto, a malevolent AI now residing in Central and itching for a code-to-code battle to the deletion with C.
A. T. It's going to take a miracle to save them, or in this case, an angel.