God told Jonah to go to a place called Ninevah to tell them that God would punish them for doing wrong things if they didn’t say sorry and change. Jonah didn’t want to go to Ninevah though so he went to Tarshish and got on a boat to sail the other way.
While on the boat they sailed into a big storm and it was so bad they thought they were going to die. The sailors found out that it was Jonah who had caused the storm because he had disobeyed God. The sailors threw Jonah into the sea and immediately the storm stopped.
God sent a big fish to swallow Jonah and he stayed inside it for 3 days and 3 nights. While he was in the fish Jonah prayed and said sorry to God for disobeying Him and said he would go to Ninevah like God had told him to do.