An introduction to chess presented as a story featuring seven-year-old twins Alice and Sam and their quest to stop an impending alien invasion. Includes information on the different pieces, check, checkmate, stalemate, basic chess strategy, and thinking skills.

The infantry -- En passant -- The chariot -- The elephant -- The queen -- The cavalry -- The king -- Check and checkmate -- Stalemate and other draws -- Pawn promotion and castling -- The values of the pieces -- Fool's mate -- Watching the enemy -- Looking for captures -- Safety first -- The guillotine -- The kiss of death -- Scholar's mate -- The queen fork -- The knight fork -- The pin -- The ambush -- The firing squad -- Alien invasion.