Mason Alan Dinehart

Mason Alan Dinehart is an American business consultant and retired actor best known for his role as a youthful Bat Masterson in 34 episodes between 1955 and 1959 of the ABC/Desilu television series The Life and Legend of Wyatt Earp, starring Hugh O'Brian in the title role of the frontier marshal Wyatt Earp. He is also known as Mason Alan Dinehart III, Alan Dinehart III, and Mase Dinehart.

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THE LIFE AND LEGEND OF WYATT EARP · S1, E33

Bat Masterson Again

Earp learns Masterson has dropped out of school and is a scout for the Army. He is being threaten by the killer Sgt. King over a woman using Bat as leverage to keep King away. Earp tries unsuccessfully to talk Bat into leaving her.
THE LIFE AND LEGEND OF WYATT EARP · S2, E13

Take Back Your Town

The George Morris gang tries to take over Dodge City while Earp and Sheriff Bassett are gone. They succeed but Bat escapes capture to catch Earp. The two decide to return to Dodge City alone but the odds against them are not promising.
THE LIFE AND LEGEND OF WYATT EARP · S2, E11

Bat Masterson Wins His Star

Bat returns to Dodge City on the stage with the lovely Nellie Wright hoping to earn a star. He quickly ends up in a gun fight and learns Nellie is part of an outlaw gang but she wants out. Bat soon finds himself a prisoner of the gang.
THE LIFE AND LEGEND OF WYATT EARP · S2, E14

Nineteen Notches on His Gun

The Dutch Henry gang is rustling cattle and killed ranch hands on some of the smaller ranches around Dodge City. Sheriff Bassett is sick and Deputy Tillman is gone so Earp and Bat decide to go undercover into the gang rather take a posse.
THE LIFE AND LEGEND OF WYATT EARP · S2, E16

Justice

Two Cheyennes have been killed, which can start a new Indian war. The Cheyenne chief plans to attack Dodge City for revenge. Wyatt Earp has no other choice but bring the killers who were scratched by the Cheyenne woman to justice.