The quick rundown: Robert Taylor & Lew Ayres are buddies. Lew returns from a trip to the Bahamas with a fiancee. Upon meeting the fiancee, Greer Garson, Robert goes to work trying to steal her heart. It works. At lunch with Greer, Robert tells her to look into his eyes, "keep staring, they'll change color." At a dinner party with Greer's parents, the hokey mom (Billie Burke) hears about this trick & tries it too. So do the rest of the female dinner guests - they don't get it. Eventually Greer & RT get married.
Back to the plot...RT works at an ad agency & Lew works for the client, a drug company. One of the new drugs they're testing is something to make you forget for a certain amount of time.
Meanwhile, working at an ad agency means long hours and a postponned honeymoon. Greer & RT decide to divorce. Enter Lew and the test drug. A couple of sprinkles into martinis and they'll forget their troubles and get back together. They forget six months & the courtship starts all over again.
The best part of the movie, which was a surprise and got a good laugh out of me, came in the last 30 seconds of the movie. I'd repeat it here but I'd spoil it. Seriously, it's good.