Max stood by the enormous metal door built into the hillside, which had been propped open to let the stream of people file in. Bellamy and Clarke hung back until nearly everyone was inside, as did Wells, who was standing watch with Sasha. “Is there anything I can do?” Clarke asked Max as they approached.

“Just make sure everyone’s settled. There are more than enough rooms, but some of them are hard to find. If anyone seems lost, you can tell them to wait for me. I’ll be down in a few minutes.”

Clarke nodded, took Bellamy’s hand, and led him through the door and down the first flight of steep, narrow stairs that seemed to descend down into the belly of the Earth. They’d both been inside Mount Weather before, but that was when they’d believed the Earthborns were their enemy, so they hadn’t spent a great deal of time admiring the incredible setup. This was no dark cave—this was a sophisticated bunker that had been built by the best engineers in America to withstand the Cataclysm.

Clarke and Bellamy made their way down the first residential corridor, a brightly lit hall lined with bedrooms on either side. At the end, a woman stood holding the hands of two small, scared-looking girls. “Do you need any help?” Clarke asked.

“All these rooms are full,” the woman said, a note of anxiety in her voice.

“Don’t worry. There’s a whole other section the next level down,” Clarke said. “If you just wait here, I’ll run ahead and find it.”

“My doll’s tired,” one of the little girls said, holding a wooden toy in the air. “She needs to go to bed.”

“It won’t take long. And you know what you can do in the meantime? You can tell my friend here all about your doll.”

“What?” Bellamy shot her a look. “I’m coming with you.”

“No extraneous activity for you. Doctor’s orders.”

Bellamy rolled his eyes, then sighed and turned to the little girl. “So…” she heard him say as she hurried off. “What’s your doll’s favorite way to hunt? Does she like spears or bows and arrows?”

Clarke grinned to herself as she imagined the look of confusion on the little girl’s face, then took another flight of stairs down and turned in the direction she assumed led to the bedrooms, but the layout of this floor was different than the one above. She backtracked and tried going the other way but ended up even more turned around.

The corridors looked different in this wing. It had fewer doors and seemed more utilitarian, like it’d been built for equipment or supplies. Sure enough, the first door she reached had a sign reading PHYSICAL PLANT OPERATIONS: AUTHORIZED PERSONNEL ONLY. Since anyone authorized to open the door had been dead for at least a couple hundred years, she figured there was no harm in sneaking a peek. She jiggled the handle. It was locked.

Clarke moved along to the next door, on the opposite side of the hall. RADIO COMMUNICATIONS: AUTHORIZED PERSONNEL ONLY the sign read. Clarke froze. Radio? She hadn’t thought about it before, but of course people would have wanted a way to communicate if they were locked down inside Mount Weather… but who would they have communicated with? If they were using this room, then presumably there wouldn’t have been anyone left to take the call. Unless… had there been other bunkers maybe? Other versions of Mount Weather?

Clarke stared at the door for a long moment, a strange, distant thought tickling the back of her mind. She couldn’t quite put her finger on it, but something about this door—that sign, those words—felt familiar. She tried the handle, but this room was locked too.

“Clarke? Did you find more rooms?” Bellamy’s voice was faint, but there was a tinge of worry to it. “Clarke?”

“I’m here,” she called back, spinning around and hurrying down the hallway toward his voice.

They finished helping everyone get settled, then went with Max, Wells, and Sasha to take inventory of the supplies. On their way to the old cafeteria, Max explained to them that his people had kept Mount Weather up and running all this time, just in case of an emergency like this.

“So you’re pretty familiar with this place, then,” Clarke said.

“I was born down here, actually,” Max replied, to her surprise. “I was the last Mount Weather baby. A few months after I was born, it became clear that the radiation levels were finally safe, and we all moved back to the surface. I still spent a lot of time down here, though. It was my favorite place to explore because the adults hardly ever came inside.”

“I can imagine. So, speaking of exploring,” Clarke said carefully, trying not to sound like she was snooping. “I found a radio room today. Do you know what it would’ve been used for?”

“Mostly for fiddling with, honestly,” Max said with a shrug. “Every generation has had a system for sending out signals on a regular basis. But no one—not once—has gotten a reply. As far as we could tell, there was just no one out there to respond.”

Clarke felt an unexpected wave of disappointment, but then another question surfaced through her sea of confused thoughts. “Did the scientists who came on the first dropship use it?”

Max looked at her quizzically, as if trying to figure out where she was going with her questions. “Actually, yes. Well, they tried anyway. They asked a lot of questions about the radio, and I even let them in to try it out but I told them what I just told you—”

Clarke cut him off. “You have the key?”