A terrorist attack at a nuclear waste site awakens aliens who were in hibernation since their 1953 invasion. A group of scientists work with the military to stop the aliens.

The aliens suffer from radiation poisoning and develop suits to protect themselves. Meanwhile, the government attempts to shut down Harrison and his team believing that the alien menace is no more.

Harrison and the team talk to a psychic woman who studied the aliens after the first invasion. Meanwhile, a group of aliens take over a family and travel cross country in order to awaken more aliens from hibernation.

The Martians continue to expand their operations. Sparked by random footage shot by a reporter Harrison's the team descend on the previously abandoned town of Breeton, where they find a bustling community that in theory should not exist.

The team is sent to Grover's Mill when it is discovered the 1938 radio broadcast of invasion was real. They meet with a group of local men who successfully fought the Martians 50 years ago and believe the Martians have returned to try and retrieve weapons abandoned in 1938.

The Martians attempt to take over a military base that has been used as a secure storage area for much of the information regarding the 1953 invasion. In particular they are seeking the location of Martians who are still in hibernation waiting to rejoin the invasion.

Suzanne learns that a friend of hers has disappeared from his college campus. Meanwhile the aliens are on campus in search of a bio-weapon.

The Martians encounter another human disease, chicken pox which is crippling their invasion plans. They decide by harvesting human brains so they can produce a cure that will put the invasion back on track. Harrison's team race against time to stop them completing their project.

Suzanne does some unauthorized research on a new kind of grain that will grow in any climate. The billionaire who invented wants to sell it to the world. Thinking poorer countries will be given money by richer countries. But the aliens have their own plans for the grain, after placing a new deadly poison in the grain, they take over the body of the billionaire who suddenly offers it free to the world.

The aliens organise a series of armoured car heists in order to finance the purchase of rubies for their new laser weapons. Meanwhile, Ironhorse is kidnapped by the husband of a woman caught in the crossfire during an alien raid on a research installation.

The aliens are forced to move their unborn infants to a refrigeration facility to save them. Meanwhile Suzanne's ex-husband, an investigative journalist appears, seeking to uncover the truth about the Blackwood project.

The team set up in Chicago to investigate a spate of kidnappings but encounter resistance from the local police. Nevertheless they discover a secret cell of alien scientists, who are trying to create a designer drug which turns addicts into frenzied killers.

Near an isolated nuclear research facility an alien scout ship is discovered. As the team arrives and set up their operations, command of the find is handed over to Colonel Alexander and his mysterious Project 9.

A competing alien race sends an assassin to eliminate the invading force and to protect humanity.