  The X-ray active RS CVn binary system Sigma Geminorum was observed during a
long-duration flare with XMM-Newton. We compare line emission during the flare
with line emission measured from a previous Chandra observation during
quiescence, in a model independent way. We find that in addition to an overall
25% flux increase, which can be ascribed to variations in the system's
quiescence activity over the 15 months that passed between the observations,
there is a hot plasma component of kT_e > 1 keV that arises with the flare. The
hot component is manifested primarily by high charge states of Fe and by a vast
continuum, but with no temperature or abundance effect on the cooler plasma,
except perhaps for Mg that is anomalously enhanced.
