April 9th, 1940. Norway is under siege. As German warships close in on Oslo, Colonel Birger Eriksen, commander of the undermanned Oscarsborg Fortress, makes a bold decision that changes the course of history. With no reinforcements, no clear order, and time running out, he makes a fateful call, launching the first shots against the German invasion and sinking the heavy cruiser Blücher. While his actions stall the enemy, delaying a full-scale invasion, they trigger a brutal response.