Robi sprints across the golden footbridge, his charcoal feet drumming on the metal planks, antenna lights flashing teal. Below him, the canal water has turned the color of cold tea.
"It's spreading fast," he calls, skidding to a stop beside Carmen, who is already leaning over the rail with a sample jar tied to a string.
She hauls the jar up and squints at the murky sludge inside. "Ew. It smells like old soup."
"It's a nutrient bloom," Robi says, his cyan eyes scanning the surface. "Fertilizer runoff washed into the canal after the storms. Too many nutrients make the algae grow wild. It gobbles up all the oxygen, and then—"
"The fish can't breathe." Carmen's face goes serious. "The water gardens. Mrs. Okafor's koi. The whole neighborhood depends on this canal."
Professor Vale arrives with her long indigo coat flapping, her silver curl catching the morning light. She studies the readings on Robi's chest display. "Oxygen levels are dropping by the hour. What's your plan, Robi?"
"Three-part solution," Robi announces, the leaf-shaped circuit on his chest glowing brighter. "Optimal and elegant."
**Attempt one:** skimmer drones. Robi releases a squadron of palm-sized flyers that dip and scoop the brown film from the surface. For twenty minutes, it works beautifully. Then the bloom simply grows back, faster than the drones can skim.
"It's like mopping a floor while the faucet's still running," Carmen says.
"Correct." Robi's speaker grille makes a small crackling sigh. "We must remove the nutrients themselves, not just the algae."
**Attempt two:** Robi unlocks a canal-side Cure pod, and living machines unfold from it—floating reed-filters with silvery stems and roots like woven copper.
