Myrna Loy play Vivian, a woman who helps a gang of jewel thieves, but not on this particular heist of some pearls. A rival gang knows that Vivian is associated with the thieves, and is watching her so that when she heads off to rendezvous with the gang that they can follow her to the pearls. And this rival gang does not consist of nice guys. They have no problem with killing people who get in their way.
Spencer Tracy is a federal agent pretending to be an ex-con so he can travel along with Vivian and apprehend the jewel thieves when she unwittingly leads him to them. But Vivian realizes he is a cop and is trying to find a way to get away from him without letting him know that she knows.
Then they run into a bad rainstorm out in the middle of nowhere and stop at the house of a man whose wife is having a baby - two of them actually. And it is there that everything changes in a way you could probably write yourself if you:
1. Are familiar with how MGM of the 1930s often shoehorned these rustic scenes into films to get the city slickers to come to their senses.
2. realize the vagaries of the production code.
3. can paint by numbers
The acting is the real reason to hang around. Myrna Loy is playing the elegant person she portrayed in so many films made after The Thin Man. Spencer Tracy is in the final phase of his "tough guy" era which he was in over at Fox and at first at MGM, even if he is just pretending to be a tough guy here. And in fact he is portraying somebody who is acting, which can't be easy to do subtly. It is interesting to see how the two play off of each other and attempt to keep up a believable front.
