The third book in Sheffield's Heritage Universe series (Convergent Series; Transvergence) further explores the magnificent artifacts and philosophy of the omnipotent Builders, but too many stock characters are introduced only to be killed off or to be funny. Survival experts and an administrator for the Fourth Alliance, Julian Graves, join the series' heroes-idealist Hans Rebka, Builder expert Darya Lang, adventurer Louis Nenda and his alien entourage, and the embodied computer, E. Crimson Tally-in a rescue mission to a galaxy in the Sagittarius Arm. During the voyage, Hans and Louis pursue their rivalry for Darya, while other crew members express their mutual dislike in a series of lame exchanges. Then, as they near their objective, the team splits up to maximize the adventures and provide, alternately, serious scientific investigation and low comedy. However, the multiple perspectives and plot leaps only fragment the gestures toward hard science, while the dramatic potential inherent in such characters as E. Crimson Tally goes undeveloped. The primary appeal will be to Sheffield devotees who feel compelled to finish a series that they've started. of The Amazing Dr. Darwin.