We present high resolution spectroscopy of a QSO whose sight-line passes through the halo of a pair of elliptical galaxies at redshift 2.38 .
This pair of galaxies probably lies at the center of a galaxy proto-cluster , and is embedded in a luminous extended Ly \alpha 
nebula .

The QSO sight-line intersects two small gas clouds within this halo .
These clouds have properties similar to those of high velocity clouds ( HVCs ) seen in the halo of the Milky Way .
The gas is in a cool ( < 2 \times 10 ^ { 4 } K ) and at least 20 % neutral phase , with metallicities in the range -3.0 < [ Fe/H ] < -1.1 and neutral hydrogen column densities of \sim 10 ^ { 19.5 } { cm } ^ { -2 } .

The origin of these clouds is unclear .
The presence of low metallicity gas within this possible proto-cluster implies either that the intra-cluster medium has not been enriched with metals at this redshift , or the clouds are embedded within a hot , ionized , metal-rich gas phase .