When the Sri Lankan navy is unexpectedly attacked by a resurgent and separatist Tamil Tiger organization, the government issues a letter of marque to former U.S. Navy officer Connor Stark. The head of the private security company Highland Maritime Defense, Stark and his eclectic compatriots accept the challenge, only to soon learn that the Sea Tigers who crippled the Sri Lankan navy are no ordinary terrorists.

The Sea Tigers have created a new weapon that not even the West possesses. By creating a localized electro-magnetic pulse (EMP), the group and its ruthless leader, Vanni, can effectively neutralize any ship, airplane, or missile. Fueled by a previously-undiscovered rare earth element for their weapon, they’re poised to achieve what they could not after losing a thirty year civil war, a threaten stability throughout the region.

Half a world away a U.S. Diplomatic Security agent is found murdered and the Iranian-born Damien Golzari investigates. Unraveling a trail which will eventually take him to the creator of the EMP weapon used by the Sea Tigers, Golzari discovers a conspiracy far more alarming for the West, including U.S. forces in the region.

Meanwhile in the forests of Sri Lanka a veteran journalist uncovers the operation to mine the element which fuels the EMP, finding the Sea Tigers have ruthlessly exploited local children for labor after killing the children’s families. After escaping capture she’s on the run, but unable to piece together the story of whom and what her captives were doing.

In between them all is Syren, a former Navy experimental vessel now the flagship of Highland Maritime, under the command of Connor Stark. Aided by the help of an old friend leading an ad hoc Navy force, Stark and his team race against the clock to prevent another and more crippling Sea Tiger attack, unraveling the mystery of the enemy and finding themselves surrounded by the Tigers. Guided by fate or just dumb luck they unite with Golzari and the journalist, hatching a plan to escape capture and return to prevent the beginning of a major regional war. But the Tigers won’t be beaten so easily, and after cornering Stark and capturing him, he’ll learn firsthand if the relationships he’s cultivated will prove strong enough to beat the odds.