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A high-resolution spectroscopic analysis is presented for a new highlyr-process-enhanced ([Eu/Fe] = 1.27, [Ba/Eu] = -0.65), very metal-poor ([Fe/H] =-2.09), retrograde halo star, RAVE J153830.9-180424, discovered as part of theR-Process Alliance survey. At V = 10.86, this is the brightest and mostmetal-rich r-II star known in the Milky Way halo. Its brightness enableshigh-S/N detections of a wide variety of chemical species that are mostlycreated by the r-process, including some infrequently detected lines fromelements like Ru, Pd, Ag, Tm, Yb, Lu, Hf, and Th, with upper limits on Pb andU. This is the most complete r-process census in a very metal-poor r-II star.J1538-1804 shows no signs of s-process contamination, based on its low [Ba/Eu]and [Pb/Fe]. As with many other r-process-enhanced stars, J1538-1804'sr-process pattern matches that of the Sun for elements between the first,second, and third peaks, and does not exhibit an actinide boost.Cosmo-chronometric age-dating reveals the r-process material to be quite old.This robust main r-process pattern is a necessary constraint for r-processformation scenarios (of particular interest in light of the recent neutron starmerger, GW 170817), and has important consequences for the origins of r-IIstars. Additional r-I and r-II stars will be reported by the R-Process Alliancein the near future.

The r-Process Pattern of a Bright, Highly r-Process-Enhanced, Metal-Poor Halo Star at [Fe/H] ~ -2