Sally and her assistants Jack Wyatt and Esther Roberts have to present a working Timepiece to the top brass in a week’s time. The only problem? It’s really hard to present time travel in the flesh. To ease the pressure, Anthony Partridge suggests a weekend trip to the newest desert vacation spot: Las Vegas, NV. But sending Sally off in public is a dangerous prospect. Will Sally’s foreknowledge of card-counting techniques and the looming Trinity nuclear test land her in hot water?
Chet Whickman, head of ODAR security, is here to break up the party. Time is ticking down til Judgment Day, but their transport vehicles break down in the middle of the desert. Sally, Chet, Anthony and his wife Helen witness the dawn of a new age of military science, and some of them realize that they may not come away from ODAR with their hands clean.