Naina arrived on Monday with two braids, a yellow pencil box, and the careful face of someone entering a room where everyone else already knew the invisible rules.
Sara decided to help. "You can sit here. The left desk leg wobbles during handwriting, but only if you press too hard."
"Thanks," Naina said.
On Tuesday, Naina brought a purple notebook like Sara's.
On Wednesday, she drew tiny stars in the margin exactly where Sara drew tiny stars.
On Thursday, she brought lemon rice because Sara had announced that lemon rice was the best thinking food.
On Friday, Naina put on Sara's thinking face: lips squeezed, eyebrow up, pencil tapping twice.
Sara whispered to Maya, "She is copying my entire system."
"Maybe she likes your system," Maya said.
"My system is not a public bench."
That afternoon, Ms. June gave the class a code puzzle. Each group had to solve a secret message made from numbers and letters. Sara reached for the paper. Naina reached too. Their fingers bumped.
"I can do codes," Naina said quickly.
"So can I," Sara said, a little too quickly back.
Sara used her usual method: A equals 1, B equals 2. The first line worked. The second line did not. The message became: Bring three socks to the moon cupboard.
Kabir leaned over. "Finally, a school rule I understand."
Sara tried backward letters. She tried every second number. She tried staring sternly at the paper. None of it worked.
Naina tapped her yellow pencil box. Tap-tap-tap-tap. Not Sara's two taps. Four taps, like a tiny drumbeat.
"At my old school," Naina said, "we used mirror codes on Fridays. You fold the page and read the numbers from the other side."
Sara wanted to say she had been about to try that. She had not.
Naina folded the paper. The silly moon socks vanished. A new sentence appeared: Look beneath the classroom clock.
Under the clock, they found a yellow envelope containing blank code cards and one instruction: Invent a code nobody else can crack.
Naina immediately covered her card with lemons. Some wore hats. One had a moustache.
"Are those letters?" Sara asked.
"Maybe," Naina said, sliding the card away. "Detectives do not reveal everything."
For the first time all week, Sara forgot to be annoyed.
At lunch, Sara sat with Naina under the window. "Why did you copy my notebook?"
Naina's shoulders rose. "At my old school, my friends and I had Friday Code Club. Here, everyone already had friends. You seemed like you knew what to do. I thought if I acted like you, maybe people would know what to do with me."
Sara looked at Naina's yellow pencil box. It was covered in stickers of tiny dancing lemons. Sara would never choose dancing lemons. That was interesting.
"You can join our table," Sara said. "But you have to bring your own code ideas. And maybe those lemon stickers, because they are strange in a useful way."
Naina grinned. "They are my thinking lemons."
The next Friday, Code Club had three notebooks: Sara's purple one, Maya's painted one, and Naina's yellow one full of mirror codes and lemon drums.
Sara wrote: Purple notebook plus yellow notebook equals twice as many codes and one hundred percent more thinking lemons.