We propose to use GMOS-N in MOS mode to obtain metallicities for roughly 100 red giant stars in the nearby (770 kpc) dwarf galaxy LGS 3. We have obtained deep imaging of LGS 3 with the Hubble Space Telescope Advanced Camera for Surveys, creating color-magnitude diagrams (CMDs) reaching roughly a magnitude below the oldest main-sequence turnoff with high degrees of precision and completeness. Dwarf galaxies like LGS 3 are of particular importance to astronomy because of the possibility to observe the fossil imprint of cosmological reionization on their early star-formation histories. Our spectra will break the degeneracy between age and metallicity that is the single largest source of uncertainty in the derivation of star-formation history from high-quality CMDs and allow for the unique and precise determination of both its star- formation history and chemical evolution. The strength of the near- infrared calcium triplet near 8600 Awill yield metallicities accurate to +/-0.2 dex and radial velocities better than 10 km/sec, allowing us to trace the abundance-kinematic connection and discover if the more metal-rich stars are dynamically colder than the most metal- poor stars, as they seem to be in nearby dwarf spheroidals. This will be the first measurement of the age-metallicity relation in a member of this enigmatic class of galaxy.