A woman arrives to serve the poor family of an inventor, who is helped by his student in developing a refrigerator.
In 1919 Indiana inventor Paul Ward (Claude Rains) struggles with his family and unpaid bills. During a snowstorm peddler Hannah Parmalee (Fay Bainter) arrives and helps Marcia Ward (Kay Johnson) cook left-overs. Paul teaches science and keeps Peter Trimble (Jackie Cooper) after school. Hannah gets Sally Ward (Bonita Granville) to set the table. Sally complains that her father picks on Peter. Hannah washes dishes, and Sally dries them. Hannah brings food from the market and persuades Marcia to hire her on the money she saves. Paul finds Hannah selling old furniture for $50. Hannah urges Paul to invent a better icebox. Paul asks Peter to help him invent a refrigerator, and Peter asks his banker father Sam Trimble (Henry O'Neill) for money. Sam tells Paul that he will write to Tom Bradford in Chicago, and in doing so Sam inquires how to adopt Peter legally.
Joe Ellis (William Pawley) sees the invention, but Peter tells Paul that he didn't. Jim stole a valve and says it was lost, but Peter finds it in the Ellis shop. Paul makes ice from water and is elated. Paul applies for a patent and get $1,000 from Sam. Sally buys new clothes, but Hannah warns her of a cold. Paul and Marcia celebrate but learn Sally is in bed after falling through the ice. Paul learns that the Ellis brothers got the patent and asks Peter how. Paul says that Peter lied. Paul tells Hannah he will fight. Dr. Thompson (J. Farrell MacDonald) tells Paul that Sally has pneumonia. Hannah encourages Paul to go on but not to fight. Hannah admits that she lost a child. Peter tells Hannah it was all his fault. Dr. Thompson says that Sally will be all right.
Marcia and Sally say good-bye and take a train to a better climate. Peter tells Paul his idea for a less cumbersome refrigerator like a percolator. Paul wires Tom about their gas refrigerator. When Paul informs Hannah that Tom and Sam are coming over, Hannah says she had a baby by Tom when she worked for his father. The Trimbles lost a baby and adopted her son. Tom (James Stephenson) tells Hannah that he knows Peter is their son. Hannah says not to disturb Peter and says she will fight; but Paul tells her not to resist. Peter explains to Tom how the refrigerator works. Tom decides not to tell Peter. Hannah kisses Peter goodnight and says good-bye to Paul before leaving.
This drama emphasizes the spiritual values of faith, trust, gentleness, service, self-sacrifice, and non-resistance rather than fighting. It suggests that the white flags of truce can be used proudly by the courageous and strong as white banners.