  Multiband CCD photometric observations of SZ Her were obtained between 2008
February and May. The light curve was completely covered and indicated a
significant temperature difference between both components. The light-curve
synthesis presented in this paper indicates that the eclipsing binary is a
classical Algol-type system with parameters of $q$=0.472, $i$=87$^\circ$.57,
and $\Delta$($T_{1}$--$T_{2}$)=2,381 K; the primary component fills
approximately 77% of its limiting lobe and is slightly larger than the
lobe-filling secondary. More than 1,100 times of minimum light spanning more
than one century were used to study an orbital behavior of the binary system.
It was found that the orbital period of SZ Her has varied due to a combination
of two periodic variations with cycle lengths of $P_3$=85.8 yr and $P_4$=42.5
yr and semi-amplitudes of $K_3$=0.013 d and $K_4$=0.007 d, respectively. The
most reasonable explanation for them is a pair of light-time effects (LITEs)
driven by the possible existence of two M-type companions with minimum masses
of $M_3$=0.22 M$_\odot$ and $M_4$=0.19 M$_\odot$, that are located close to the
2:1 mean motion resonance. If two additional bodies exist, then the overall
dynamics of the multiple system may provide a significant clue to the formation
and evolution of the eclipsing pair.
