Saga was a large, gray, extremely opinionated cat. She lived in a house with a garden, and every autumn she arranged her collection of stones in a very precise, very important line along the path. One stone per day. Perfectly straight. This was simply how things were done. But tonight, from her perch on the back step, Saga saw something deeply suspicious. Her stones were gone from the path. Every single one. In their place, out in the middle of the snow, something round had appeared. Saga's whiskers twitched. She dropped off the step with a soft crunch.
*Nose down, paws slow.* The snow was packed hard and the cold air smelled of pine and something else — something small and warm and recent. Saga moved in a wide circle around the edge of the garden, reading the ground with her nose the way other cats read nothing at all. There were tracks. Tiny ones. Smaller than her own, and much closer together, pressed in a dotted line across the white. *Nose down, paws slow.* She followed them to the base of the old oak tree, where the roots humped up through the snow like shoulders.
And there, tucked between two roots, was a snow fort. Round walls. A low doorway. Her stones — her stones — pressed neatly into the base of every wall, holding the whole thing together. Saga sat down and stared. A small brown nose appeared in the doorway. Then two round ears. Then a mouse, who looked up at Saga without any particular expression of guilt. "Oh," said the mouse. "Hello. I'm Seb."
Saga stared at Seb. Seb looked at Saga. "The stones," said Saga, very precisely, "were arranged in a line." Seb nodded. "They were," he agreed. "But they're the exact right size for a fort wall. I tried acorns first. The acorns rolled away." He said this as though it explained everything, which, Saga had to admit, it did. *Nose down, paws slow.* Saga walked the full perimeter of the fort, inspecting each wall. The stones were well placed. The gaps were filled with packed snow. The doorway faced away from the wind. She had some notes, but they were small notes. What she noticed most was the roof — or rather, the place where the roof should have been. Flat sticks lay scattered in the snow, each one having clearly fallen in. "Three nights," said Seb, from the doorway. "I cannot get the roof to hold."
Saga sat. She looked at the walls. She looked at the sticks. Then she looked at three of her stones — the flat ones, the ones she'd found by the stream — still sitting in a pile near the oak tree. She picked one up in her mouth, carried it to the fort, and set it across the gap. Then another. Then the third, angled in to lock them together. The roof held. Seb pressed on it with one paw. It did not move. He pressed harder. Still nothing. He looked up at Saga with his mouth slightly open. Saga gave the fort one slow blink. Then she turned and walked back across the garden — *crunch, crunch, crunch* — up the back step, and through the door.
Inside, she found her mat by the door. She stepped onto it, turned once, and settled, paws tucked under her chest, tail wrapped around her side. The cold air still clung to her fur. Outside, the snow fort stood in the dark between the oak tree's roots, solid and round, three flat stones locked across the top. Case closed.
