  There is evidence for an excess of gamma rays with $O({\rm GeV})$ energy
coming from the Galactic Center in data from the Fermi Telescope. The spectrum
of the excess is well fit by 30 GeV dark matter annihilating into a pair of $b$
quarks with a cross section expected from a thermal relic. For an explanation
of this excess, we study a renormalizable model where dark matter couples to
the SM via a pseudoscalar that mixes with the $CP$-odd Higgs boson of a Two
HIggs Doublet Model. We report the constraints on this model from direct
detection, Higgs decays, and rare $B$ meson decays.
