Gideon watched as the water swirled around the tunnels, carrying the Pines with it.

The blast had caught the shapeshifter too, but he didn't much care. As long as he grabbed the Journal and got out of here before anyone could reorient themselves, everything would go perfectly.

As soon as the way was clear, Gideon left the pipe, grimacing at the orange rust that had rubbed off on his black gloves as he'd turned the wheel. The sooner he was out of this filthy place, the better.

He sidestepped past Stanford, Dipper, and Candy, who were coughing and spluttering in a heap on the floor. Neither the Journal nor the shapeshifter's hulking form was anywhere to be seen.

His eyes raked the ground for the Journal as he turned the corner to return to the lab, the bright lights making him feel exposed despite his invisibility. He was still looking when he almost tripped over something. He looked down.

What his eyes found wasn't the Journal, but an orange lump on the ground.

Gideon's heart leapt to his throat. It was Mabel.

And she wasn't moving.

He fell to his knees at her side, rolling her over to get the hair out of her face. Her hair was so thick! It felt like an eternity to get it out of the way so he could check if she was breathing.

Her chest wasn't rising or falling, but when he bent over, he thought he could feel a faint breath on his cheek. Was he just imagining it? Was she—?

He activated his amulet, trying to check her for thoughts or any kind of brain activity. His hands flickered into view, and he jumped before realizing that he had turned visible. Of course. He couldn't do two things at once.

A part of him screamed at the rest of him to stop panicking, to get ahold of himself, but it was too small to have any effect. Which was why he spent a few seconds thinking Mabel was brain-dead before remembering that he couldn't read her mind.

"Mabel," he said, shaking her shoulders gently — or maybe not so gently. "Mabel, get up. Breathe. Come on. Come on!"

This was his fault; this was his fault; he did this; he turned on the water—

One of Mabel's eyes opened.

Gideon breathed in sharply. "Mabel!"

"I'm not Mabel," she hissed.

"Wh-what?"

"It's me, Shifty. The shapeshifter?"

Gideon stared at her — it — for a moment before shoving it away. "What! What are you doing, pretending to be Mabel?"

"I thought her family would find me, not you!" Shifty-Mabel sat up, glaring at Gideon, whose panic was quickly giving way to anger.

"I can't believe you would—"

"Kid," Shifty-Mabel said suddenly.

"No, listen, if I freaked out, imagine—"

"Kid, turn invisible. Now."

"What?"

Shifty was looking over Gideon's shoulder, and Gideon turned before he could stop himself.

Mabel — the real Mabel — was standing behind him, staring at him with wide eyes.

Gideon turned invisible and ran, dashing back to the entrance of the tunnel, but the damage had been done. How could he have been so stupid!

Across the room, the shapeshifter got to its feet. "Where's the Journal, child?"

Mabel's eyes locked on Shifty's. "S-stop it," she said. "Stop looking like me."

"Does it unnerve you?" Shifty spoke in Mabel's voice. Gideon didn't like it. "Give me the Journal and I promise I'll stop."

"I-I don't have it," Mabel said. But her eyes glanced out to the side, betraying her lie. Gideon looked over to see the dull gleaming of the hand set on the Journal, shoved halfway behind a cryogenic tube.

Shifty-Mabel saw it too.

It snarled and dashed across the room. Mabel cried out and tried to get to the Journal too, but Shifty-Mabel was faster, and it snatched the Journal out from under Mabel.

Mabel tackled herself.

There was a flurry of orange and brown as the two Mabels fought over the Journal. Gideon was strongly reminded of the time he helped Mabel fight her clones. Except this time, the clone was a shapeshifter out for blood.

Gideon couldn't tell which Mabel was which, but he could guess that the one losing terribly was the real Mabel. The panic on her face couldn't be faked.

The panic on her face.

Something switched on inside Gideon, and he set his jaw. Mabel had already seen him — he wasn't going to let Shifty hurt her.

He rushed for them, turning visible right before his fist connected with Shifty-Mabel's face. He'd better be right.

Shifty-Mabel howled. The sound was inhuman — so Gideon was right. "What are you doing?" Shifty bellowed in its own voice.

"Get away from her!" Gideon said, activating his amulet and lifting Shifty-Mabel into the air. He threw the shapeshifter across the room and watched it crash into the far wall. Once again, he was reminded of the clones. This time of the clone he had killed by impaling her on a stalactite.

He turned back to Mabel, whose eyes were wide and afraid. "G-Gideon — what are you—"

Gideon knelt down. "I don't have time to explain."

"H-how—"

She didn't finish her sentence. He braced himself for the surprise in her gaze to give way to hatred, the way it had last time she had seen him.

The hatred didn't come.

The relief that swept through him was much stronger than he would have imagined.

Gideon reached out and grabbed Mabel's hand tightly in both of his. "I'm betraying someone right now," he said, "to save you. I hope this can begin to make up for what I've done."

She stared at him.

He glanced at the Journal, and she did too. How close it was, how easily he could grab it and run away, just like last time. . .

Just like last time.

He took a deep breath and picked up the Journal. Mabel visibly flinched.

No. Not again. He couldn't do that to her again.

Gideon handed it to her.

Her stare widened even further. She took it from him, but he kept one of her hands in his.

His eyes traced the golden six-fingered hand for a moment before he forced his gaze away from the Journal and back to her.

"I. . . I'm sorry, Mabel," he said. "For everything."

He lifted her hand and kissed it gently.

She snatched it away. But when he looked up at her, there was no anger in her eyes, only shock. It was just reflex.

He let go of her hand and stood up. "I hope you can forgive me someday," he said softly.

Then he slipped away.

He waited until he had gone around a corner before turning invisible. No need for Mabel to know how he got down here.

Once he was sure he couldn't be seen, he crept back to the lab to watch.

"Mabel!"

There was Dipper. He came racing into the lab, Candy and Ford behind him.

"D-Dipper!" Mabel didn't get up, just reached out for her brother. "Shifty — he's over there — I think he's unconscious — Ford, you gotta use the stun gun while he's still in that form!"

Dipper looked over at Shifty, then back at Mabel. His eyes narrowed. "How do we know you're not the shapeshifter, and that's not the real Mabel over there?"

"You had your first kiss with a selkie named Amanda," Mabel gasped.

Dipper smiled in relief. "I knew it was you. I just wanted to be sure."

A moan sounded from across the room. Shifty-Mabel twitched.

Ford whirled around and shot the stun gun, but Shifty-Mabel was too fast. It rolled away from the blast, jumping to its feet and snarling at the Pines.

"Not again," Gideon heard Mabel whisper.

Candy stepped forward. "That's it." She rolled up her sleeves. "It's time to do this my way."

She rushed at Shifty.

Shifty-Mabel turned just in time to see her. Its face went blurry as it started to change shape.

Candy slammed into it, knocking it back down to the floor. Gideon lost sight of the shapeshifter for a moment, but soon Candy was thrown back to reveal its new form.

The shapeshifter had become Candy.

Shifty laughed, its guttural voice unnatural in Candy's throat. It dodged another shot from Stanford. "I wouldn't do that," it said. Its voice became higher and higher as it spoke, until it sounded just like Candy's. "You wouldn't want to hurt the real Candy, would you?"

The real Candy, who had been running for Shifty, skidded to a stop as she seemed to realize what this meant. But it was too late. Shifty-Candy turned and grabbed Candy's upper arms, turning her and shoving her into the wall. Candy's head hit the stone with a sickening thud, and she didn't move for a moment.

"Candy!" Dipper yelled. He was across the room, kneeling next to Mabel, in no position to help.

Candy's eyes stopped swimming and bored into Shifty-Candy with rage. Then she tackled Shifty-Candy to the ground.

The two Candys tumbled over the ground, latched onto each other, until Gideon had no idea which Candy was which. Which was Shifty's plan, of course.

Dipper got up to help, but Ford shouted him down. "I have to get a clear shot!"

"You'll hit her!" Dipper shouted back.

Stanford growled in frustration. "Candy, get out of the way!"

"I'm trying!" Both Candys yelled it together.

Ford aimed his stun gun into the brawl, then helplessly put it down. Gideon frowned. Even if he made the shot, what then? Would they freeze Shifty again? How long until the cryogenic tube failed and the shapeshifter got out again?

A reminder went off in his brain. Note to self: Dispose of this creature before you leave.

Gideon's eyes roamed the room until he saw Ford's pack, discarded on the floor. He started towards it. He knew how to stop this. 

You'd better have a real gun in there, Stanford.