Oliver quickly covered the vent with his hand.

“Wait!” he said. “That coin is mine!”

The tiny people froze.

The one with the brown coat stepped forward.

He looked nervous.

“Well… yes… technically…” he said in a squeaky voice.

“But we borrowed it.”

“Borrowed?” Oliver said. “You didn’t ask!”

The tiny man sighed.

“We are the Wall Keepers,” he explained.

“We collect coins that fall, drop, or get forgotten. Coins help us fix our tunnels and doors.”

Oliver crossed his arms. “But that coin didn’t fall.”

The tiny man looked embarrassed. “Yes… we may have… taken that one.”

Just then the tunnel behind them shook.

Dust fell from the wall.

A loud cracking sound echoed.

“Oh no!” one of the tiny people shouted.

“The tunnel is collapsing!”