A comprehensive account of the properties of southern hemisphere (SH) Polar Mesosphere Summer Echoes (PMSE) has been constrained by the lack of deployment of atmospheric radars. Here we present the first complete season of PMSE detected above the high-latitude station Davis, Antarctica (78.00E, 68.60S) using a 55-MHz atmospheric radar for the 2004--2005 austral summer. We present the characteristics and morphology of SH PMSE events observed during the interval 23 November 2004--18 February 2005. Coincident Aura satellite temperature measurements (T) and ground MF-radar partial reflection observations are used to investigate the thermal and dynamical state of the polar mesosphere during conditions of PMSE occurrence. We find that the seasonal envelope of PMSE corresponds remarkably well with the seasonal envelope of temperature or more precisely when T - Tfp < 0 K (Tfp = frost point temperature). Furthermore, we show that PMSE are linked with the typical summer equatorward flow of the mesosphere meridional wind, but were perturbed while this wind flowed poleward.