Please to remember/ The Fifth of November/ Gunpowder, treason and plot,"" the rhyme enjoins, and in British stories the burning of Guy Fawkes' effigy is a ready reminder; just how the Catholic scheme to blow up King, Lords and Commons on Parliament's opening day was carried forward, and why it failed, is the substance of Miss Cooper's tight little novel. She has invented, she says, only what records fail to provide, but she does not withhold comment, to the effect that the conspirators separated ""being Catholics"" from ""behaving like Christians."" For the rest, Guy Fawkes, recalled to England by prime-mover Robert Catesby to engineer the explosion, is a solitary, iron-willed and impassive; Catesby is the charmer who wins over the thirteen (the thirteenth will undo them); Tom Percy, cousin to the Earl of Northumberland and therefore privy to his power, is the one who never wavers when even Catesby, in the face of imminent discovery, would abandon the plan. They have tunneled stealthily, tediously, before discovering the cellar to let under Parliament House; twice seen the opening of Parliament postponed; blanched at Frank Tresham's fears for his brothers-in-law, especially for his ""dear Monteagle."" And then Monteagle receives an anonymous warning and, sensible of the recency of his conversion to Protestantism, hastens to the King and his first Minister, the fanatically anti-Catholic Cecil -- a wise man, Cecil, who lets the King draw the obvious conclusions. It's a rounded, deepened drama that reads like the knell of doom, and of course it did doom the Catholics to two hundred years' more repression.