What begins as a simple investigation of a peculiar subspace signal leads to an errand of mercy, as the da Vinci responds to a distress call -- from the edge of a black hole! Hundreds of years ago, the Resaurians placed a station near the event horizon, forever teetering on the edge of the abyss, and now the S.C.E. must find a way to rescue them.

But the black hole, known as "the Demon," contains centuries-old secrets that the Resaurians will kill to protect -- and both the U.S.S. da Vinci and the station may be sacrificed to the Demon in order to preserve those secrets!