When two former Red Sox players--partners in a bid to wrest ownership of the team from the rich widow Dougherty--are both murdered at Fenway Park during an Old-Timer's Day reunion, retired sportswriter Duffy House and his hubba-hubba niece Petey are asked to investigate. Two more ex-players will die (including another would-be club owner); Boston homicide cop Fred Parent will develop a crush on Petey while Duffy swoons over a classy widow; and the chief suspect, a groundskeeper, will disappear before a cancer- riddled old sportswriter writes a confession, then gulps a toxic handful of pills. His sports-announcer son seems more upset that the old man also poisoned the dog than that dad died--and then further investigation by Duffy, Petey, and Fred climaxes at the Red Sox-Yankee game during a 20-minute blackout. Their plot can't quite cut the (ballpark) mustard, but William Brashler and Reinder Van Til--using the Evers pseudonym for their fourth (and first hard-cover) Duffy House adventure--clearly love the sport. For fans, then, there's plenty of baseball trivia.