This is Poirot at his best. Investigating a cold case – a wife was convicted of murdering her philandering husband. Everyone believes she did it except for their child who was only 5 at the time. She comes to Poirot to find the truth. He interviews each suspect, or little piggy, and discovers what really happened on that day.
Interesting, complicated characters. Perfect pacing. Classic misdirection. Probably one of my favorite Christie mysteries.