Right away, you're struck by the pace, the tempo of operations. This is a ship at war, in the thick of battle.
"This is the most intense deployment I've ever been on," says Cmdr. Jim McDonald, chief of ordnance, or "weapons boss," and a 27-year Navy veteran. "It's been non-stop."
Since Dec. 29 2015, the Truman, a Nimitz-class aircraft carrier, has played a crucial role in the campaign against ISIS in both Syria and Iraq.
It's an awesome weapon.
Almost 20 percent of all the ordnance dropped on ISIS this year has come off of this ship.
Aircraft from the Truman have dropped more precision-guided munitions -- "smart bombs" -- during this deployment than any carrier in any deployment in U.S. history.
But last week, the Truman arrived in the Mediterranean, not far off the coast of Syria.
"It's a demonstration of our capabilities -- we can go anywhere in the world, and we don't need permission," Rear Admiral Bret Batchelder, commander of the carrier strike group, tells me. "And we're making a difference here."
Batchelder flies missions off the ship. Weekly.
"It helps me understand what our pilots are going through," he says modestly, but his hell-for-leather grin gives away his fighter pilot's heart.
The men and women of the Truman who drop all those bombs on ISIS seem to believe in this particular mission: to help degrade and destroy ISIS.
"I'm grateful my country lets me do this, go up there and take it to them," Lt. Kallie Billings says, adding that ISIS's attitudes about women are an extra motivation.
Her message to ISIS? "I'm here!"
She is an electronic warfare specialist, blinding, silencing, confusing ISIS communications from 20,000 feet.
"Whatever they're using -- it's mine," she boasts.
The pilots and warfighters on the Truman may have the glamour jobs.
But this is a ship with 5,000 sailors on board.
And when you spend some time seeing their work up close -- from the bridge to the hangar to the galleys to the berths below -- you get a sense of the enormous effort that goes into every single sortie, every single attack launched from this ship.
And every single sailor plays a role.
Way down below decks, in the maintenance administration offices of one of the air squadrons, airman Ali Alsayagh works.
Born and raised in Baghad, Alsayagh served as a translator with the U.S. Army from 2003 until 2009. So did his father.
But then -- their lives in danger -- the two men and their families fled to Iraq.
Alsayagh moved to Virginia, under a special visa program enacted by Congress to help Iraqis, like Alsayagh, who helped American forces.
He and his wife started a family and have three kids now. Alsayagh recently became an American citizen.
Then, last year, he decided to join the Navy.
"I wanted to serve my country," Alsayagh says.
So here he is, on the USS Harry S. Truman, taking the fight to ISIS.
Like all those on board -- an American serving his country.