Maigret, not so much his subdued self as he's been lately, is approached by a little very old lady who says that her house has been disturbed and that it's a ""matter of life and death"" which it indeed becomes. The inquiry quickly narrows down to her ugly, aggressive niece and her pimp-lover, and a few soft words from Mme. Maigret make its solution easier. A good one in this continuity where everything is simply stated and reaches its source -- and quiet flows the Seine.