Ethan Hunt (TOM CRUISE) is a covert I.M.F. agent who's been assigned by his superior (ANTHONY HOPKINS) to track down a former agent, Sean Ambrose (DOUGRAY SCOTT), who's acquired a dangerous biotech product known as Chimera from Dr. Vladimir Nekhorvich (RADE SHERBEDGIA). The problem is, since the researcher is now dead, no one knows what the product is or does, where Ambrose has it stashed, or what he plans to do with it.
As such, Ethan's boss wants him to assemble a team to find Ambrose, with the condition being that one member of the team must be Nyah Hall (THANDIE NEWTON), an alluring professional thief who once dated Ambrose. This complicates matters for Ethan since he's just slept and thus fallen for the woman.
Nonetheless, he arranges for Nyah to seamlessly fall back into Ambrose's life. With her being equipped with a traceable implant, Ethan, and his two associates, Luther Stickle (VING RHAMES) and Billy Baird (JOHN POLSON), track her movement and discover Ambrose's lair.
From that point on, and as Ambrose deals with a biotech corporate official, John McCloy (BRENDAN GLESSON), about Chimera -- that turns out to be a lethal and contagious virus that kills its victims in twenty hours -- Ethan and his team must find, attain and give the antidote to a person infected with the virus while avoiding Ambrose and his men, including his lieutenant, Hugh Stamp (RICHARD ROXBURGH).