really slowly, knees crooked inward, dragging her feet. She was one of Deaâs first friends. Dea and Mira made up elaborate stories about the other residents of the condo, invented a new language called Inside Out, and buried treasure in the potted plants so that aliens would someday find it.
The day it happened, theyâd spent the morning pretending to be scientists, inventing names for every flower they could think of, drawing them carefully with crayons in a big book of heavy-duty artistâs paper Miraâs dad had bought her, of which Dea was insanely jealous. She was jealous, actually, of everything Miraâs father did, even stupid things, like coming down to the courtyard and telling Mira when it was time to come up for dinner, standing with one hand on the door, looking impatient.
She was jealous that Mira had a dad at all.
It was hot. Even the pool was too hot to give much relief, notthat Dea would have swum or even known how. Instead, Mira had the idea to drag a lawn chair into the pool house, next to the foosball table, where there was a fan. At some point, they fell asleep, lying next to each other in their shorts and T-shirts, their feet just touching.
And Dea found herself walking down a narrow stone corridor, open to the air on both sides and half collapsed, as in a castle gone to ruin. As she moved forward, the stone shifted and re-formed into individual doorways.
Later, she learned from her mom that this wasnât uncommon. The dreamer, sensing an intrusion, builds walls, buildings, sometimes whole cities, to prevent the strange element, the walker, from getting inâkind of like the body releases white blood cells to the site of an infection.
But Miraâs mind wasnât very practiced, and so Dea passed easily through one of the doorways and ended up in the open, standing on a vivid stretch of green grass. Walking someone elseâs dream was like moving through a strangerâs house. Everything was unfamiliar, and Dea knew instinctively not to disturb or touch anything.
On a tennis court several hundred feet away, Mira was playing. She was running back and forth on legs that were both strong and straight, and each time her racquet connected with the ball, there was a satisfying thwack . Then, midair, each ball turned into a bird and soared away. Soon there were dozens of birds, circling overhead, as though waiting for something.
Even at six, Dea knew that she was trespassing on something very private.
All at once the birds converged and became an enormous kite, so large it blotted out the sky. Then the court was swallowedin shadow and she knew it was time to wake up.
Outside the little pool house, it was raining. And for the first time in Deaâs life, her heart was beating normally.
Her mom knew what sheâd done. At the time, Dea didnât think that was strange. She was Mom . She knew everything. She knew how to make the perfect chicken soup by adding cream and tomato to a can of Campbellâs. She knew how to catch a single raindrop on her tongue. She knew mirrors and open water were bad, and clocks were good.
That day, Miriam sat at the kitchen table, gripping a mug of tea so tightly Dea could see individual veins in her hand, and explained the rules of walking.
The first rule, which Dea had already intuited, was that she must never try to change anything or intervene in another personâs dream.
The second rule, related to the first, was that she might walk as many dreams as she wished if she was careful, and followed all the rules, but she must never walk the same personâs dreams more than once.
And the third rule was that she must never, ever be seen.
Her mother explained other things, tooâthat birds were harbingers and would serve as guides, that mirrors and water were places where the boundary between the worlds was the thinnest, that clocks would keep them safe from the other sideâbut Dea had barely listened, so disappointed