Event Horizon Drift

A crewed probe mission orbits Sagittarius A*, the supermassive black hole at the Milky Way's center, testing time-dilation instruments for interstellar navigation. When the station's local clocks begin to diverge from Earth-based synchronization in a way that can't be explained by relativity, a physicist suspects a massive drift in the black hole's accretion disk is triggering temporal anomalies. The mission becomes a race to collect the final readings before falling past the innermost stable orbit.