  We compare quiescent and flare X-ray spectra of the RS CVn binary Sigma Gem
obtained with the Chandra and XMM-Newton grating spectrometers. 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 > 3 keV that arises with
the flare. The hot component is manifested primarily by emission from high
charge states of Fe and by a vast continuum. The cooler (kT_e < 2 keV) plasma
remains undisturbed during the flare. We find no significant variations in the
relative abundances during the flare except for a slight decrease (<30%) of O
and Ne.
