Imani’s mouth twitches, almost a smile. “Say why light is food.”

You put it in grower words. Leaves use photons like coins. In the light they stitch carbon dioxide and water into sugar and breathe out oxygen. In the dark they nibble their own sugar and breathe a little CO2 like people do. A dust storm spends the coins before they reach the glass. Fine dust on the glass spends more.

Oskar spins a plot on the tablet. “She’s not wrong. ‘Air’ can look fine while the plants starve for photons. That’s a quiet failure. Quiet failures still count.”

Imani nods once. “Then we need lamps that make PAR, and glass that isn’t wearing a brown sweater. We can do the interior wand and the LED banks and still make it, or we can tell ourselves plants can nap in the dark because naps are restful. I have watched plants nap. They get tall and pale and useless. Etiolation. A fancy word for stretching toward a sun that left.”

The clock in the corner reads three hours fifty to thick weather.

GROVE: “Direct PAR at canopy: falling. LED banks: available. Exterior EVA window: closing with visibility.”

You picture the packet they made you read on the shuttle that was not this problem: spectra, stomata, boundary layers. Leaf Hall is a greenhouse, not a magic trick. Photons have to do some of the work.

A stomata is a mouth on a leaf, too small to see and too important to tease. In the light, those mouths drink carbon dioxide. In a still room they drink slowly. In a dark room they mostly close and the plant lives on savings. Savings are not a personality. Savings are a number that storms spend.