  We present high resolution optical echelle spectra and IUE observations
during a strong flare on 1993 December 22 in the very active, young, rapidly
rotating, single K2 dwarf LQ Hya. The initial impulsive phase of the flare,
which started sometime between 2:42 UT and 4:07 UT, was characterized by strong
optical continuum enhancement and blue-shifted emission lines with broad wings.
The optical chromospheric lines reached their maximum intensity at
$\approx$5:31 UT, by which time the blue-shift vanished and the optical
continuum enhancement had sharply decreased. Thereafter, the line emission
slowly decreased and the lines red-shift in a gradual phase that lasted at
least two more hours. The Mg II lines behaved similarly. Quiescent C IV flux
levels were not recovered until 21 hours later, though a data gap and a
possible second flare make the interpretation uncertain. In addition to the
typically flare-enhanced emission lines (e.g., H_alpha and H_beta), we observe
He I D_3 going into emission, plus excess emission (after subtraction of the
quiescent spectrum) in other He I and several strong neutral metal lines (e.g.,
Mg I b). Flare enhancement of the far UV continuum generally agrees with a Si I
recombination model. We estimate the total flare energy, and discuss the broad
components, asymmetries, and Doppler shifts seen in some of the emission lines.
