The story of Queen Athaliah can be found in the Old Testament of the Bible, specifically in the book of 2 Kings (2 Kings 11:1-21) and the book of 2 Chronicles (2 Chronicles 22:10-23:21). Here is a narrative of the whole story:
Once, in the kingdom of Judah, there arose a queen named Athaliah. She was the daughter of the wicked king Ahab of Israel and his equally wicked queen, Jezebel. Athaliah married Jehoram, the son of the righteous king Jehoshaphat of Judah. However, Jehoram walked in the ways of the wicked kings of Israel and brought idol worship and evil practices into Judah.
When Jehoram died, his son Ahaziah succeeded him to the throne. Ahaziah followed in his father's sinful footsteps, and his reign was short-lived. After just one year, he was killed in a conflict with Jehu, the new king of Israel, who had come to power through divine judgment against the house of Ahab.
Upon hearing of her son's death, Athaliah saw an opportunity to seize power for herself. She ruthlessly murdered all her grandchildren who were in line to inherit the throne, effectively wiping out the royal bloodline and ensuring her rule. Only one baby boy, Joash, the son of Ahaziah, was saved from her wrath. He was secretly taken by his aunt Jehosheba and hidden in the temple of the Lord.
For six years, Athaliah ruled as queen over Judah, spreading wickedness and idolatry throughout the land. However, in the seventh year, the hidden child Joash was revealed to the high priest Jehoiada. He was anointed as the rightful king in a secret ceremony within the temple.
At the age of seven, King Joash was presented to the people. The momentous occasion took place in the temple, and the coronation was met with great joy and celebration. When Athaliah heard the jubilant cries of the people, she rushed to the temple to see what was happening.
To her horror, she discovered that her reign had come to an end. The loyal soldiers and priests were united behind young King Joash, and the wicked Athaliah was seized. Jehoiada ordered her to be taken outside the temple grounds and put to death for her atrocities.
With the death of Athaliah, the rightful line of kings was restored to the throne of Judah, and King Joash went on to rule with the guidance of Jehoiada the priest. Under their joint leadership, the land of Judah experienced a period of revival and reform, as the evil practices brought in by Athaliah were eradicated, and the worship of the Lord was restored.