Helen steals the only phial of the deadly biological weapon, Opaque, while her boyfriend, Daniel, steals a helicopter. Together they head towards the coast, with Daniel ignorant of Helen’s true motives of vengeance on the man she believes responsible for her husband’s death. Things start to go wrong when the helicopter malfunctions. Losing control of the craft, Daniel is forced to crash land on a mountainside. He is badly injured in the impact while Helen escapes with only minor cuts and bruises. While still wondering what to do, Helen hears the sound of an army Chinook helicopter approaching. As it lands close by she has to act fast to save herself if she has any hope of continuing with her mission. With reluctance she kills Daniel, making it appear as if he died in the crash. Through deception and more murder she obtains her immediate goal to take control of the Chinook. Threatening to break the phial of Opaque she forces the soldier/pilot, Chris, to take her to the Oil Rig in the North Sea. As they hover above the rig, Chris makes his move to take the phial from her and in the struggle the phial is dropped. Cornered and lost, Helen jumps to the decking below. Badly injured and dying on the rig, she catches glimpses of the rig personnel gathering around her, and amongst them is Ryan. Before she dies in his arms, she realizes she had been cruelly deceived and betrayed. While the Chinook still stands on the rig’s helipad, Chris accidently treads on the phial and releases Opaque. The dull yellow gas kills him instantly. As the gas escapes the craft and creeps slowly over the rig, it delivers Helen’s vengeance to almost everyone it touches. Even a group of Special Forces soldiers sent to contain the situation find Opaque a formidable enemy from which not many survive