Tallinn, Estonia - Things are bad on the small island nation of Berylia after a diplomatic row with Crimsonia, its bigger neighbour and rival. There are street protests by the Crimsonian minority in Berylia, which then suffers a wave of cyber-attacks that make it lose control of its drones and its only international airbase. Crimsonia is blamed for the cyberoffensive even though there's no hard proof. Crippled by the attacks, Berylia, a new member of the North Atlantic Treaty Organisation (NATO), weighs its options. One of them is to invoke Article 5 and take the military alliance to war against Crimsonia.

Sean Ruddy and his team of operator-soldiers from the US Cyber Brigade entered a Locked Shields, a NATO-organized cyber-defense war game that pits teams from dozens of countries against "live-fire" attacks. It was their first time. And of the 19 countries represented, the US finished dead last. This week, they got their shot at redemption. Locked Shields challenges participating countries to show off their defensive prowess, rather than offensive firepower.