The title is drawn from the defiant cry reportedly uttered by Sparta's King Leonidas I to Persians demanding that he surrenders his army's weapons, Molon labe ("Come and take it").
At the same time, Maggie and Hal are nearly attacked in the tunnels by a swarm of spider-like creatures seemingly sent by the aliens to force man's hand.
In the meantime, Jamil is revealed to have been made into a "Trojan horse" as several creatures erupt from his body and chase Anne, Lourdes and Matt, trapping them in the blood lab.
Matt is sent through the air vents by Anne to fetch help and narrowly avoids being eaten by the creatures thanks to being found by Tom and Pope and is pulled out in time.
Karen appears again to tell the resistance it has run out of time and callously executes a captured fighter (Boon) to prove a point.
Her attitude changes when presented with the injured Overlord and she has to be restrained to hear Tom's proposition: Let the humans leave and she gets her master back to treat.
The explosives are connected to a detonator that is with a hidden Pope and if he sees or gets word of trouble he will blow the building up, killing Karen and her master.
After Ben leaves on foot to join the skitter rebellion, the Second Mass begins the final leg of their journey to Charleston.
In its original American broadcast, "Molon Labe" was seen by an estimated 3.45 million household viewers, according to Nielsen Media Research.