We have members of the Ark spread out in this week's episode of The 100, but things are moving forward on all fronts. While the adults try to establish some semblance of order on the surface, Clarke learns the dark secret lurking beneath Mount Weather.
Now that the adults have taken control of the situation on the ground, they have to deal with the very things the kids have been dealing with for weeks: inadequate supplies, injured members, and a mysterious foe. Kane is quick to take charge, locking Bellamy up until he gets the intel he wants and banning anyone who isn't trained military from carrying guns. I wonder how well this gun control will work in a frontier community.
But Kane quickly learns there are certain things he can't control. The Ark survivors discover three of their number pinned up with arrows and spears, an apparent message that the survivors should stay out of the woods. And Abby has to perform an anesthesia-free surgery to remove the bullet from Raven's body; Raven survives, but the nerve damage means that, at least for the time being, she'll be on crutches.
When Abby points out how brave the 100 kids are to Kane, there is a note of "unlike us." Abby wants to push their scouts into the woods to find the Grounder camp, thinking the other kids—including Clarke, might be there. Kane, probably wisely, preaches caution. He wants to know what they're dealing with before they go charging into the woods. So Abby takes matters into her own hands, arming a secret team of 100, including Bellamy and Murphy, and sending them to find the Grounders camp. When Kane realizes what's going on, he may find himself dealing with a power struggle.
Octavia, meanwhile, has lost Lincoln, but gained Michael, a friend of Lincoln's. Lincoln's little bid for forgiveness didn't go so well, and he's being punished by his people. Michael treats Octavia's delirium before telling her to run, and Octavia repays his kindness by bashing him on the head and using him as a hostage. I'd say you catch more flies with honey than with rocks to the skull, but Octavia does succeed in setting up a prisoner exchange, Michael for Lincoln. It all goes so well until the Reapers show up. Nuts. Welp, I guess Octavia will have to go to Lincoln's village and form an alliance with the Grounders there. Reapers, you guys show up at the most conveniently inconvenient times.
I idly wondered at the end of last episode whether Thelonious had gone mad, and it tuns out he has, but it's a productive sort of madness. Now that he has a baby with him, Thelonious decides he has to get down to the surface, and concocts a plot to launch himself toward a missile that he can ride down to Earth. For added drama, he has to spend seven minutes in space while wearing a spacesuit with a cracked helmet. Naturally, the helmet explodes on the way over, but close enough to the missile that Thelonious survives. But when he reaches for the baby that he swore he stuck in his spacesuit, he finds nothing but blankets. The baby was a figment of his imagination.
Thelonious thought he was ready to die, but some part of him wants to live. That part of him takes the guise of his dead son, and coaxes him to take the missile to Earth, baby or no baby. So he takes the plunge and heads to Earth—but where, exactly, has he landed?
Okay, who called that the Undergrounders were using Grounders for their blood? You get a sticker.
Clarke is still not making any friends in Mount Weather, and it's pissing her fellow 48 off. They're nervous that, with all the accusations she's throwing around, she's going to get them kicked out of the land of chocolate cake. But that does stop Clarke from bursting right into the medical ward when a couple of members of the surface surveillance team turn up injured, one with radiation burns and another with some sort of projectile injury that Clarke is certain is a bullet wound, but which the Undergrounders insist came from an arrow.
Clarke may be wrong about the bullet wound, but she's right to be suspicious of the Undergrounders. After brutally reopening her arm wound, Clarke gets herself checked into the medical ward where the burned surface scout is receiving his final radiation treatment. We're told that the Undergrounders receive dialysis to deal with radiation exposure, but Clarke quickly notices that the blood isn't simply going into the machine and coming back out again; it's traveling outside of the room. Really, guys? You couldn't have hidden your blood pipes better?
Clarke follows the blood pipes and learns the horrifying secret of Mount Weather: the dialysis machines are people. Human beings from the surface are suspended and fitted with tubes, pumping their nice, clean blood into the Undergrounders. The scout team isn't simply surveying the surface; they're hunting Grounders. And if there was any doubt where they've been hunting, Anya is trapped in one of their cages.
So, we've got a lot of possibilities here. Do the majority of Undergrounders know about this little arrangement? Wallace seems to view the Grounders as subhuman, but is that the general consensus? Will there be members of the 48 willing to accept this cruelty for comfort? Will the Grounders want to destroy Mount Weather, or will they recognize the benefit of a place filled with medical and agricultural technology? And what will the adults at Camp Jaha have to say?