Memorial Day is thriller novel by Vince Flynn, and the seventh to feature Mitch Rapp, an American CIA agent that works for the counter-terrorism unit "Orion Team".

Intelligence gathering has indicated unusual activity in financial markets, and Rapp, back in the field after a long stint on desk duty for insubordination, unearths a bomb plot during a daring commando raid on an al-Qaeda stronghold in Afghanistan.

However a United States strike force manages to intercept and disarm the nuclear weapon moments after it arrives by freighter in Charleston, South Carolina.

Everyone, including series stalwart President Robert Hayes, congratulates themselves on a job well done, but Rapp is not convinced; he believes al-Qaeda leader Mustafa al-Yamani has smuggled a second nuclear weapon into the country and plans to detonate it in Washington, D.C., during Memorial Day celebrations.

When a missing Pakistani nuclear scientist is found to have passed through LAX on his way to Atlanta, and a truck driver turns up dead due to radiation sickness, the chase is on again.