According to Genesis, Ham saw his father Noah uncovered. Genesis 9:20–24 describes Noah planting a vineyard, becoming drunk, and lying uncovered inside his tent; Ham, identified as the father of Canaan, saw him and told his two brothers.
Shem and Japheth responded differently. They took a garment, walked backward into the tent, and covered Noah without looking at him. When Noah awoke and learned what had happened, the passage records a pronouncement involving Canaan, Ham’s son.
This episode follows the Flood narrative and is separate from the Ark’s construction or voyage. It has generated extensive interpretation because the text’s precise offense and the resulting curse have been debated by Jewish and Christian commentators. The passage does not say that Ham built the Ark, nor does it identify him as the youngest son; Genesis simply names him in the family account.