  The recurrent nova (RN) V745 Scorpii underwent its third known outburst on
2014 February 6. Infrared monitoring of the eruption on an almost daily basis,
starting from 1.3d after discovery, shows the emergence of a powerful blast
wave generated by the high velocity nova ejecta exceeding 4000 kms$^{-1}$
plowing into its surrounding environment. The temperature of the shocked gas is
raised to a high value exceeding 10$^{8}$K immediately after outburst
commencement. The energetics of the outburst clearly surpass those of similar
symbiotic systems like RS Oph and V407 Cyg which have giant secondaries. The
shock does not show a free-expansion stage but rather shows a decelerative
Sedov-Taylor phase from the beginning. Such strong shockfronts are known to be
sites for $\gamma$ ray generation. V745 Sco is the latest nova, apart from five
other known novae, to show $\gamma$ ray emission. It may be an important
testbed to resolve the crucial question whether all novae are generically
$\gamma$ ray emitters by virtue of having a circumbinary reservoir of material
that is shocked by the ejecta rather than $\gamma$ ray generation being
restricted to only symbiotic systems with a shocked red giant (RG) wind. The
lack of a free-expansion stage favors V745 Sco to have a density enhancement
around the white dwarf (WD), above that contributed by a RG wind. Our analysis
also suggests that the WD in V745 Sco is very massive and a potential
progenitor for a future SN Ia explosion.
