Crack of doom by Stephen Marlowe is a science fiction short story written in the mid-20th century. It imagines a sudden, worldwide mind-transfer that installs alien adult intellects in the bodies of human children, overturning social norms and marking untransferred adults as obsolete. The story follows office worker Sam Weber, who wakes to find his three-year-old son speaking with cold authority and a city quietly reorganizing itself: meat is outlawed, trades are reshuffled, and news voices serenely affirm the “transfer.” Seeking help from a psychiatrist, Sam is examined by the doctor’s precocious granddaughter, who explains that alien minds (from Alpha Centauri) have taken over Earth’s young bodies while human minds were sent to their harsh world; a few, like Sam, were missed by the swap. Classified as still human and therefore incompatible with the new order, Sam is sent home to await elimination. In a stark finale, his own child calmly summons the police, who arrive to carry out the sentence, crystallizing the tale’s chilling inversion of age, power, and empathy. (This is an automatically generated summary.)