Domino has discovered a dark secret in the heart of Eastern Europe. A border dispute threatens to spread into an international incident. The leaders of Puternicstan have an army of black-market Sentinels, and they're ready to take the fight to neighbors Latveria and Symkaria! Storm leads a strike team of Utopia's most powerful mutants - Warpath, Psylocke, Colossus and Jubilee - to rescue Domino and scuttle the Sentinels. But standing between the X-Men and their mission is the iron man known as War Machine. NATO seeks to block the team's incursion - sparking a three-way war between the mutants, War Machine and a Sentinel army dangerously close to igniting World War III! Plus: a classic X-Men tale featuring the origins of the Sentinels! Collecting X-MEN (2010) #20-23 and X-MEN (1963) #14.