Ian Howe is the main antagonist in National Treasure, a skilled financier and treasure hunter. He was after the Templar Treasure and does not care who he has to kill or what he has to destroy to do so.
Ian finances a trip to the Canadian Arctic, specifically the lost ship Charlotte, where Benjamin Franklin Gates says there is a treasure waiting for them. Ben thinks at this point that Ian is just another treasure hunter, he does not know that Ian is a criminal that will do anything to get money. When they find the Charlotte, there is no treasure waiting for them, just a bunch of gun powder and another clue. This clue leads to the Declaration of Independence. Ian says the only way to see the back where the clue is to steal it and he intends to do so. When Ben and his friend Riley Poole say they do not want any part of it, Ian threatens them by having his henchmen, Shaw, hold a gun on them. He threatens to shoot Riley if Ben doesn't give them he rest of the clue. But Ben threatens to drop flame on the gunpowder, which would blow them all up. The fire does end up on the floor, causing Ian and Shaw to run for their lives. After this, Ian thinks Ben and Riley are dead, and doesn't find out the truth until the stealing of The Declaration. Ian then heads for Washington D.C. At the Watergate Complex, Ian along with some henchmen create a plan to steal the document. However, Ben decides to save the document and beats Ian to it. Ian figures out that the next clue leads to Philadelphia and is outsmarted at the Liberty Bell by Gates and his friends by stroke of luck. Ben now had the Declaration and goes to New York City, where the next clue leads.
Ian has to make a deal with Gates friends because only Gates can figure out the final clue. It leads to Trinity Church in New York and, to make sure that Ben and his friends do not pull a double cross on him, he kidnaps Ben's father Patrick Henry Gates. The two Gates, however, trick Howe into thinking there is one last clue which leads to the Treasure at the Old North Church in Boston. The treasure, which was in Trinity Church, is found by the Gates who tell the FBI that Ian and his henchmen are at the Old North Church in Boston. Ian is captured and thrown into jail.
Based on federal jail time standards, Howe will probably be released from jail between 2015 and 2020.