Enigma Ship
Enigma Ship is a Pocket SCE eBook novella – #20 in the series – written by J. Steven York and Christina F. York. Published by Pocket Books, it was first released in . The novella was later collected in the SCE omnibus .

Summary 
From the book jacket
Sent to investigate the mysterious disappearances of several Federation starships, the USS 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!

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eBooks