Second Kings is a record of the fall and conquest of the Northern Kingdom, which is Israel, and the Southern Kingdom, which is Judah. We know that this division took place from about 850B.C. to 560B.C.
The Assyrians conquered the kingdom of Israel and took most of the people north to Assyria. After this 'scattering' of the ten tribes of Israel, there is no record of what happened to them, except for a reference which is acknowledged in the Book of Mormon that says the Savior visited some of them.1 They are now known as the lost ten tribes of Israel.
The book also acquaints us with the prophets Elijah, Elisha, and Isaiah. It then ends with the account of the Babylonians conquering the kingdom of Judah and carrying the people away captive into Babylon. This captivity occurred approximately between 605-587B.C. These accounts of destruction and captivity fulfilled the prophetic warnings of Moses and Samuel.2
1 Book of Mormon; 3 Nephi 17:4 2 Old Testament; Deuteronomy 8:10-20, 1 Samuel 12:14-15, 24-25