“A trunk?” Tobias suggested.

Margo nodded. “And what has a trunk?” It wasn’t a question. She put her hand over the image of an elephant, said loudly, “Open!”

To everyone’s surprise except Margo’s, it did.

Tobias whistled as the door cracked open. The tunnel continued beyond it, to a far-off glimpse of daylight at the end. “Nice trick,” he said.

“It will be different for the next person,” Margo cautioned. “Faery doors always are.”

“When did you become an expert on Faery?” Tobias asked.

“Last night,” Margo said with a sideways glance. “The Faery Code is available online.”

The door shut behind them with a clang of finality.

“How did you know what to do with the door?” Bruno asked, as he crouched to clear the doorframe, following Margo through. The tunnel was, if anything, even lower past the door.

“Gates and bridges always whisper their secrets,” Margo said.

“Magic?”

“Not like spells or witchcraft,” Margo was quick to explain, glancing back over her shoulder at Bruno. “It’s more like shifter strength. A natural part of being a troll.”

“Like my keen sense of smell,” Bruno agreed.

“I don’t have a sense of smell,” Margo said, and Bruno thought she sounded regretful. “Maybe this is what I have instead.”

“How curious,” Bruno said. He worried that it didn’t sound as admiring as he felt, but it was hard to converse to Margo’s back end, however nice it was, when they were both half-bent over and scuttling down a damp tunnel like lost crabs.

Hug her, his cave bear advised unhelpfully.

That’s your solution for everything. “What else should I know about Faery?”

“Don’t say thank you,” Margo cautioned. “Faery takes debts very seriously and thank you can imply a favor owed. You don’t want a faery owing you a favor.”

“What about please?”

“Please is perfectly safe.”

The floor of the tunnel crunched like gravel underfoot and Bruno tried not to imagine that it was the bones of trespassers.

“What’s our plan of attack once we get there?” Bruno asked. Margo was so astonishingly capable, he might be intimidated if he wasn’t so enraptured with her.

“There’s no way to take Eva by force,” Margo cautioned. “Faery magic isn’t about strength, and we have no power here anyway. I will have to open a challenge for her hand.”

“Shouldn’t that be me?” Bruno wanted to know. Margo was gorgeously strong and fierce, but it was hard to top a cave bear in battle or brute strength.

“Do you trust me?” Margo stopped so abruptly that Bruno ran into her from behind.

Hug! his cave bear insisted, and Bruno let himself indulge. “I trust you,” he said faithfully.

It was not the most graceful hug, with both of them stooped beneath the short stone ceiling, but he felt Margo relax gratefully into him. “Then let me challenge.”

As they walked, she told him more. “Under current code, challenges in Faery are very peculiar. A challenge may be brought against anyone, once. The challenged chooses the battlefield, the challenger chooses the weapons.”

It was certainly challenging to track all of the parties, Bruno thought. “What about me?”

“If I fail, you can challenge again, your way, and you have three days to do it. Things in threes are important to them, like the three impossible tasks and the three nights spent at a lover’s door that you hear in stories.”