We outlive capitalism. In a post-scarcity society, people do things not out of desperation but for joy. Xavi loves nothing more than putting on a silicon tail and swimming as a mermaid. She performs for children. Xavi encourages them and their parents to protect the clean water of the city's canals. A community treasure, she is the first person who comes to mind when excited doctors develop a surgery to turn someone into a merperson. Xavi pioneers it, pushing the boundaries of transhumanism.
Then the mermaid goes missing.
A local citizen detective discovers Xavi had texted them "help" the night before, when their devices were silenced. The Citizen Detective Society mobilizes across the globe. They hope to crowdsolve the mermaid's location and soon. Every passing hour reduces the probability they'll discover her alive.