Enigma Ship — J. Steven York

Sent to investigate the mysterious disappearances of several Federation starships, the U.S.S. da Vinci discovers a true technological marvel: a holographic vessel. Commander Sonya Gomez and her S.C.E. team try to navigate the different holographic scenarios playing inside the "holoship," and are surprised to find the crews of the missing ships -- who think they've been rescued!
Gomez and her team must convince the crews that they are trapped in an endless holographic program, or risk losing them forever!