  As part of an All-Sky Automated Survey for SuperNovae (ASAS-SN) search for
sources with large flux decrements, we discovered a transient where the
quiescent, stellar source, ASASSN-V J192114.84+624950.8, rapidly decreased in
flux by $\sim55\%$ ($\sim0.9$ mag) in the g-band. The \textit{TESS} light curve
revealed that the source is a highly eccentric, eclipsing binary. Fits to the
light curve using \textsc{phoebe} find the binary orbit to have $e=0.79$,
$P_{\rm orb}=18.462~\text{days}$, and $i=88.6^{\circ}$ and the ratios of the
stellar radii and temperatures to be $R_2/R_1 = 0.71$ and $T_{e,2}/T_{e,1} =
0.82$. Both stars are chromospherically active, allowing us to determine their
rotational periods of $P_1=1.52$ days and $P_2=1.79$ days, respectively. A
LBT/MODS spectrum shows that the primary is a late-G or early-K type dwarf.
Fits to the SED show that the luminosities and temperatures of the two stars
are $L_1 = 0.48~L_{\sun}$, $T_1= 5050~K$, $L_2 = 0.12~L_{\sun}$, and $T_{2} =
4190~K$. We conclude that ASASSN-V J192114.84+624950.8 consists of two
chromospherically active, rotational variable stars in a highly elliptical
eclipsing orbit.
