Miss Seeton's summer outing to a tennis match serves up more than expected when Britain's up-and-coming female tennis star is hounded by death threats. The girl's father, stem Judge Thumper, seems to have provoked one of the miscreants passing before his bench -- and the target of the ex-convict's wrath is the athletic Miss Thumper. The police are counting on Miss Seeton to unravel some baffling clues before victory goes to the villain . . . game, set, and match.