  We present time-series near-infrared (NIR) spectra for the classical Cepheid,
CP Cephei, from the Astrophysical Research Consortium 3.5-m telescope and NIR
spectrograph, TripleSpec, at Apache Point Observatory, NM, USA. Spectral
observations were made at three points on the ascending portion of the visible
phase diagram for the star. Carbon monoxide (CO) was detected in absorption in
the 2.3-micron band head for each observation. We observed that the equivalent
width of the 3-1 transition of the CO band head decreased by half from our
first observation to the second, or slightly over one day out of the 17.867-day
period. Our third observation occurred 54 days after the first (slightly over
three periods for the star) and showed similar CO levels to the first
observation, suggesting that the CO is in the stellar atmosphere and varies
with pulsation.
