With Season 2 of Falling Skies starting on June 17th, it's a good idea to go over what we might have forgotten about during Season 1. And if you're a johnny-come-lately, good for you! Now you don't have to watch every Season 1 episode in order to watch Season 2 at the same time as everyone else (but really, you should watch Season 1...it's awesome, we promise.)
Several races of aliens have come to Earth. They have destroyed most of the world's military and 90% of the human population. Not only are the extra terrestrials killing off the humans, but they are kidnapping human children for something, controlling them through bio-magnetic harnesses...to turn them into Skitters too.
To save Earth from these invaders (known as Skitters and Mechs, the humans must rely on the The 2nd Mass, the human group, with second-in-command Tom Mason, who plans to overthrow the evil aliens and get back to life as we knew it.
Tom Mason is the second in command of The 2nd Mass, a group that plans to defeat the aliens. He was previously a professor of history at Boston University, but uses his knowledge of warfare to his advantage when fighting the aliens. He's got quite a bone to pick with the aliens, however. They murdered his wife and kidnapped his son Ben. At the end of Season 1, Tom Mason agrees to let the Overlords take him, because they promise that if he does as they please, his son will not become a Skitter.
Daniel Weaver is in charge of The 2nd Mass. He is an army soldier, so he is even better fit for the job than his second-in-command, Tom Mason. When the aliens first attacked, he bravely fought them, but now he has even more of a reason to want them all dead: not only did they kill his family, but they attached a biomagnetic harness to his very young daughter, Sophia. When he tried to remove her harness, she died. At the end of Season 1, he looked on worried as Tom Mason agreed to be taken by Overlords.
Anne Glass is the doctor of The 2nd Mass. She used to be a pediatrician, but now has a lot more on her plate. Like most of the members of The 2nd Mass, she is grieving for her deceased family members: specifically, her husband and son. Although both she and Tom Mason are going through tremendous emotional stress, their friendly relationship and high positions in The 2nd Mass has led them to have a romantic connection. However, it is not clear where things are going: at the end of Season 1, Anne Glass and Tom Mason kissed, but since Tom allowed the Overlords to take him, we don't know where Anne will be when, or if, he gets back.
Hal Mason is the son of Tom Mason and he was a junior in high school before the invasion. He is the boyfriend of Karen Nadler, a teenage girl who joined The 2nd Mass to avenge the death of her family. She has been captured twice. First, she was captured by Pope's Gang (and released by female operative, Margaret upon hearing that she would be raped). She was also captured by the skitters when she and Hal Mason attempted to save his younger brother Ben. Since then she has been harnessed, and the Overlords use her to communicate with humans.
Skitters are nocturnal, spider-like aliens that were believed to be responsible for the invasion of Earth in Season 1. They pose a huge threat because they kidnap children, strapping them to bio-magnetic harnesses that turn them into skitters themselves, even if the harnesses are removed. However, when Anne Glass and Lourdes dissect the dead body of a skitter, they realize the skitter has one of the harnesses on, which means that they are not the true invaders, but rather unwilling drones or slaves of a higher alien race (Overlords)--and they could have once been human.
The Mechs are robots who fight alongside the skitters. They can shoot bullets and rockets from their arms. They also have lasers, which are blue while targeting but once locked on, they turn orange. Mechs can also fire an energy beam to stun humans, which is often used when they are stunning children they wish to harness. The Mechs possess two arms, one manipulator-arm with a clawed hand (capable of tearing into a schoolbus), and another "arm" that is really a weapons-stub for a built-in gun. The clue that the Mechs were designed by Overlords is that unlike skitters, they walk on two legs, not six.
The Overlords are the apparent rulers of the skitters. They most likely designed Mechs as well. They were not discovered until seven months after the initial invasion--presumably they had skitters do their dirty work because they were too afraid to explore Earth while there were still so many humans around. At the end of Season 1, they want to negotiate with Tom Mason, and if he agrees to do as they say, they will agree to prevent his son, Ben from turning into a skitter. They also have The 2nd Mass member, Karen Nadler as their slave, who gives messages to humans for them.
The 2nd Mass is a human militia composed of surviving individuals after the invasion of Earth, most notably Daniel Weaver, Tom Mason, and Anne Glass. It is one of the groups that make up the Massachusetts Militia (which is led by Commander Porter, presumed dead at the end of Season 1). The 2nd Mass is composed of both civilians and fighters, which started out totaling about 200 people, and its headquarters is at the John F. Kennedy High School in a suburb outside of Boston.
Pope's Gang is a group of criminals led by John Pope, a felon, and his right-hand man, his brother Billy Pope. They have fought and killed Skitters, but they are overall a threat to The 2nd Mass because they have held their members hostage in exchange for weapons and money. They kidnap Karen Nadler in the episode, The Armory. When Billy Pope hints that he's going to rape Karen, a member of Pope's Gang, Margaret, sets Karen free and joins Tom Mason and the others as they attack John Pope and the gang. It is later revealed that this change of heart comes from the fact that she was sexually abused by Billy Pope.