When Dorothy and her little sister Fay move into the house next to that occupied by Jack and his little brother Steve, Cupid giggles and holds some target practice. His arrows land just as Fay sticks her tongue out at Steve, and Dorothy turns up her nose towards Jack, across the aisle while they attend church. Lacking the finesse of her elder sister, Fay determines to get on speaking terms with Steve. Learning that Jack is a doctor, she falls sick. Dorothy runs for the physician and thus friendship starts. Matters failing to develop rapidly enough for Cupid, the little imp places a book on the Habits of Primitive Man, on Jack’s table. The brothers find it. When Jack reads aloud how the cave men wooed their lady-loves, an idea enters Steve’s mind. Steve buckles right down to business when he, Fay, Dorothy and Jack are in the park. Grabbing hold of Fay, Steve plants a strenuous kiss upon her nose. Indignant, the girl slaps him. Jack and Dorothy witness the incident. When Jack attempts to interfere, Dorothy bids him leave the children alone. One long glance toward Fay and Steve, and Jack, seizing Dorothy in his arms, emulates his little brother’s example. Dorothy struggles in vain. Fay has ceased fighting, as her elder sister observes from the corner of her eye. And Cupid, peeping from behind a nearby tree, hops about in glee when he sees the result of his work.