How can a tiny mosquito be such an enormous threat to humankind? And how is it that this once distant threat is now lurking in our own backyards? Filmed on four continents and featuring breathtaking macro photography, Mosquito paints an emotionally charged portrait of the people who are now living with mosquito borne diseases and we in North America who fear their arrival.

Bob Harrison takes his family to spend the summer in a dilapidated cottage on Mosquito Lake where he grew up alongside neighbour George, who still lives there full time.

Police lieutenant detective Thomas 'Thom' Randall's steady girl-friend, Dr. Jennifer 'Jen' Allen, is Dr. Aaron Michaels's main assistant on his pharmaceutical firm Bellion's research program to cure the highly contagious, fatal infection Guinin. A convicted murderer, whom Thom arrested, is one of their special drug test subjects, but escapes. The convict and Jen are affected by radioactively altered DNA from an experimental reactor used on mosquitoes which transfer quinine. The convict soon mutates into a mosquito-like monster, which sucks its victims dry. By the time Thom and his junior murder brigade partner Charlie Morrison figure out what happens, Jen starts mutating herself.

Allie Fox—a brilliant inventor and stubborn idealist—uproots his family for a dangerous quest through Mexico to flee the U.S. government and find safety.