Faced with making a decision that could result in the destruction of an entire world, the chief engineer must determine whether his double is a friend or a foe—and in whose universe the two crews have ended up.

This volume concludes a three-part storyline from writer Michael Jan Friedman that began in the previous collection, then tackles the issue of toxic waste on a global scale. Finally, Friedman revisits Will Riker’s days aboard the U.S.S. Hood.