  Young planets provide a window into the early stages and evolution of
planetary systems. Ideal planets for such research are in coeval associations,
where the parent population can precisely determine their ages. We describe a
young association (MELANGE-3) in the Kepler field, which harbors two transiting
planetary systems (Kepler-1928 and Kepler-970). We identify MELANGE-3 by
searching for kinematic and spatial overdensities around Kepler planet hosts
with high levels of lithium. To determine the age and membership of MELANGE-3,
we combine new high-resolution spectra with archival light curves, velocities,
and astrometry of stars near Kepler-1928 spatially and kinematically. We use
the resulting rotation sequence, lithium levels, and color-magnitude diagram of
candidate members to confirm the presence of a coeval $105\pm$10 Myr
population. MELANGE-3 may be part of the recently identified Theia 316 stream.
For the two exoplanet systems, we revise the stellar and planetary parameters,
taking into account the newly-determined age. Fitting the 4.5 yr Kepler light
curves, we find that Kepler-1928 b is a $2.0\pm0.1R_\oplus$ planet on a
19.58-day orbit, while Kepler-970 b is a $2.8\pm0.2R_\oplus$ planet on a
16.73-day orbit. Kepler-1928 was previously flagged as an eclipsing binary,
which we rule out using radial velocities from APOGEE and statistically
validate the signal as planetary in origin. Given its overlap with the Kepler
field, MELANGE-3 is valuable for studies of spot evolution on year timescales,
and both planets contribute to the growing work on transiting planets in young
stellar associations.
