In his 35th and last Keystone comedy, Charlie Chaplin parodied the recent hit, D.W. Griffith's stone-age drama, Man's Genesis. Charlie is caveman Weakchin, dressed in derby, cane and bearskin. He plucks some fur from his bearskin and fills his pipe with it, lighting the pipe by picking up a stone and striking it against his thigh. He is an outsider, invading the territory and harem of King Lowbrow (Mack Swain). At first welcomed by the King, Weakchin persists in wooing Sum Babee (Gene Marsh), one of Lowbrow's favorite wives. Eventually the men clash and Weakchin kicks Lowbrow over a cliff. Taking over the leadership of the tribe, Weakchin repairs to the King's cave with Sum Babee. Rescued by his sycophantic court jester, the King sneaks into the cave and clobbers Weakchin from behind with a rock, whereupon Charlie the Tramp awakes on a park bench with a cop looming over him -- it has all been a dream -- the first of many dream sequences in Chaplin's films.
by Phil Posner synopsis