A lecherous landlord tries to steal a woman from her fiance.

Collegian Robin Austin persuades her boyfriend, David, to live with her platonically to discover whether they are psychologically compatible. She takes an apartment recently vacated by Dr. Irene Wilson, her instructor in marriage counseling. Her new landlord is Hogan, an unabashed, incorrigible Casanova; he has just had an affair with Irene, who now has a new beau, Charles Howard, an associate professor. Not realizing that David is his new tenant's "roommate," Hogan plans to seduce her; then, discovering the true state of affairs, he employs every stratagem to keep David and Robin apart. At a crucial moment, Irene, accustomed to Hogan's antics, arrives in time to save Robin's virtue. By this time, David, thunderously angry, decides to plan a quiet night with Robin with soft lights, music, drink, and poetry and let nature take its course; but when Robin has reached a stage of acquiescence, David remorsefully runs from the apartment. Finally, David and Robin decide to elope, and Irene becomes completely involved with Charles, leaving Hogan alone--until he rents the apartment to a new beauty. Hogan is back in business.