Tom is haunted by memories of his time with the aliens. Pope plants seeds of doubt about him among the group. Ben’s hatred for skitters grows. The 2nd Mass locate a bridge that will help them cross the river to safety ahead of an impending attack.

Weaver is still in command of the 2nd Mass, while Anne continues to serve as medic. They have seen many battles and are a much leaner unit now. Pope has taken command of the Berserkers, a renegade group within the 2nd Mass that Weaver doesn’t fully trust.

With Weaver leading several squads of fighters against the aliens, Tom remains behind to help protect the civilians as they evacuate. But a major breach in security endangers both the soldiers and the civilians. Tom is confronted with a decision that may lead him to discovering what the aliens want with the captured teenagers, humankind and the planet.

As the 2nd Mass. prepares for a major assault, divisions within the ranks threaten to tear the group apart. Tom has difficulty processing the profound implications of Anne’s latest discovery.

The 2nd Mass prepares to take the fight to the invaders with an assault on one of their bases. But Weaver’s increasingly strange behavior worries Tom that he might not be fit to command. Hal and Tom encounter a left-behind woman who employed a suspicious means of surviving the invasion, making it unclear whether they can trust her.

Hal takes the lead fighting an unexpected threat against the children of the 2nd Mass. Anne has her hands full when Sarah goes into labor while the 2nd Mass base is being evacuated.

Lt. Terry Clayton of the 7th Mass arrives with word that the aliens are on their way to attack the 2nd Mass. Clayton’s plan to lead the children to a safe haven while the adults remain behind to fight is met with some resistance from the parents, including Tom.

Hal comes up with a risky new plan to rescue captured teenagers from the aliens, but it might require putting someone at risk. Meanwhile, a sudden tragedy causes Anne to make an enormous discovery that proves instrumental to Hal’s risky plan.

Tom and his team head out to track down more motorcycles for the 2nd Mass., relying on Pope to guide them to a good location. They hit the jackpot until they meet some skitters and harnessed teenagers at the bike shop. Back at the base, Dr. Harris and Anne disagree over the best method to gather more intelligence on the aliens.

Dr. Michael Harris joins the 2nd Mass with a theory about what might save the teenagers abducted by the aliens. But the plan could be derailed when Tom starts digging for answers to questions that have haunted him since the early days of the invasion. The 2nd Mass comes face to face with skitters and mechs when they attempt to rescue Ben.

While scouting for supplies, Tom, Hal and their squad encounter a gang of marauders determined to get their hands on the 2nd Massachusetts’ weapons. Leading the gang is an ex-con named John Pope, who decides to use his hostages as bargaining material.

The world is left in tatters after a sudden, unprovoked and unexplained invasion by aliens, leaving the planet’s remaining human population to fight for survival against the occupiers. History professor Tom Mason has been named second in command for the 2nd Mass, but his real focus is on his three sons, one of whom has been captured by the aliens for an unknown purpose.

Veronica and Keith follow a new lead, and discover another victim. Matty follows her own instincts, landing herself dangerously close to a killer. Veronica has a tragic epiphany as the clock is ticking.

Veronica debates coming clean to Nicole. Veronica’s fidelity is tested. Veronica and Keith discover they aren’t the only ones who believe they’ve found the bomber. A surprising potential client tries to hire Mars Investigations.

As Veronica learns more about Nicole’s past, her suspicion deepens. A frantic phone call from Paris leads to a search for Matty. Veronica unwittingly does legwork for Leo.

Veronica discovers Keith has been hiding something scary from her. The real reason for Penn’s latest theory on the bomber comes to light. Veronica loses confidence in new friend, Nicole, owner of Comrade Quacks.

Convinced the bomber is still at large, Veronica visits Chino to learn more about Clyde and Big Dick. Mayor Dobbins’ request for help from the FBI brings an old flame to Neptune. Veronica confronts her mugger.

Veronica and Keith’s client, Daniel Maloof, makes a shocking confession. Sheriff Langdon closes in on her top suspect. Veronica and Matty join forces, just as the whole investigation is flipped on its head.

Veronica and Keith launch their investigation. Their involvement puts Police Chief Langdon on edge. Penn goes public with his theory on who the bomber is. Meanwhile, local teen Matty Ross begins her own search for her father’s killer.

Panic spreads through Neptune when a bomb goes off during spring break. Veronica and Keith are hired by the wealthy family of one victim injured in the bombing to find out who is responsible.

Up against the clock, Morgan, Grace, and Alicia work to buy time as Dorie and Dwight race against the elements. Meanwhile, Sarah and Wendell get help from an unexpected source.(TD)

Faced with mounting problems on the street, Franklin pivots his business model. Andre investigates a murder connected to Franklin’s family. Teddy uses Gustavo to help broker a new deal in Mexico, then receives a surprise visitor upon returning home.

Harvey and Samantha fight to keep Zane’s name on the wall. Alex warns Louis of the consequences.