Jonah was a prophet who was the son of Amittai. He was told by God to preach a message of repentance to the wicked city of Nineveh, but refused. God sent a fish to swallow him after he got thrown overboard a ship headed towards Tarshish that was caught in a God-sent storm. After God had the fish vomit Jonah onto land, He had Jonah go to Nineveh and preach the message. The people responded, God spared them, but Jonah was not happy. God taught him a lesson of forgiveness. This is recorded in the book bearing his name.
During the time Jonah the prophet was alive, Nineveh was a very wicked city. Nineveh was also the capital of Assyria. God told Jonah to go to Nineveh and tell them to repent, but Jonah ran away. He went to Joppa and found a ship headed to Tarshish. He boarded that ship and went to sleep below deck. God sent a violent storm upon them, and the ship threatened to break up. The captain asked Jonah how he could sleep, and told him to pray to his God. The captain hoped that one of the gods (however there is only one God) would take notice of them and save them. The sailors cast lots to see who was responsible for the calamity and the lot fell on Jonah. They began questioning him, asking him who he was, what he did, where he came from. Jonah explained to them what he had done. Jonah suggested that he be thrown overboard so the sea will be calm. The sailors didn't like the idea and tried rowing back to shore, but couldn't. The storm got worse. The sailors asked the LORD to spare them and not be held accountable for killing Jonah. Then they threw him overboard. God provided a huge fish (might be a whale, might be something else, the Bible doesn't say) to swallow Jonah to keep him from drowning. For three days Jonah was inside the fish, praying to God. After three days, God commanded the fish to vomit Jonah on dry land. 
God commanded Jonah to go to Nineveh and preach to them what He would tell him. Jonah obeyed this time (probably didn't want to be eaten by a fish again) and went to Nineveh. Nineveh was so large that it took Jonah 3 days to preach to everyone there. Nineveh had walls that were 8 miles long, surrounding an area of 1,700 acres. Jonah told them that Nineveh was going to be overthrown in 40 days. They believed God and proclaimed a fast. Everyone from the greatest to the least wore sackcloth as a sign of mourning. The king, Assur-dan III, heard of Jonah's warning and took off his royal clothes, wore sackcloth and sat down in the dust (also a sign of mourning). He made a proclamation that no one, not even the animals, could eat or drink anything. Both people and animals had to wear sackcloth, and everyone was to call urgently on God. They were to give up their evil ways and their violence. The king hoped that God would relent from His fierce anger. God did relent from destroying them when they did what the king said to do. They were very willing to do this because of recent events. The Assyrian kingdom was at a low point. Assyria suffered military reverses, diplomacy setbacks, famine and domestic uprisings. Also, an eclipse had occurred on June 15, 763 BC. This could have been seen as a terrible omen. Then Jonah shows up with his message from God.
Now Jonah wasn't happy that God spared them, so he became very angry. Jonah knew this would happen, and was the reason why he ran away, trying to stall this from happening. God asked if it was right for him to be angry. Jonah went to a place east of Nineveh and built a shelter to shade him from the sun. He waited to see what would happen to the city. God provided a leafy plant to grow and give Jonah better shade. A worm killed the plant and a scorching wind blew into Jonah's face making him grow faint. He wanted to die and was angry about the plant dying. God asked if it was right for him to be angry about the plant and Jonah said it was, and he is so angry that he wished he was dead. God asked him if he shouldn't be concerned about more than the 120 thousand people in Nineveh who don't know their right hand from their left, when Jonah was concerned about a plant that sprang up overnight and died overnight.