  We present high-resolution $K$-band emission spectra of the quintessential
hot Jupiter HD 189733 b from the Keck Planet Imager and Characterizer (KPIC).
Using a Bayesian retrieval framework, we fit the dayside pressure-temperature
profile, orbital kinematics, mass-mixing ratios of H$_2$O, CO, CH$_4$, NH$_3$,
HCN, and H$_2$S, and the $\rm ^{13}CO/^{12}CO$ ratio. We measure mass fractions
of $\rm \log H_2O = -2.0^{+0.4}_{-0.4}$ and $\rm \log CO = -2.2^{+0.5}_{-0.5}$,
and place upper limits on the remaining species. Notably, we find $\rm \log
CH_4 < -4.5$ at 99\% confidence, despite its anticipated presence at the
equilibrium temperature of HD 189733 b assuming local thermal equilibrium. We
make a tentative ($\sim3\sigma$) detection of $\rm ^{13}CO$, and the retrieved
posteriors suggest a $\rm ^{12}C/^{13}C$ ratio similar to or substantially less
than the local interstellar value. The possible $\rm ^{13}C$ enrichment would
be consistent with accretion of fractionated material in ices or in the
protoplanetary disk midplane. The retrieved abundances correspond to a
substantially sub-stellar atmospheric $\rm C/O = 0.3\pm0.1$, while the carbon
and oxygen abundances are stellar to slightly super-stellar, consistent with
core-accretion models which predict an inverse correlation between C/O and
metallicity. The specific combination of low C/O and high metallicity suggests
significant accretion of solid material may have occurred late in the formation
process of HD 189733 b.
