  We construct the action for N M2-branes on $S^1/{Z}_2$. The resulting theory
has a gauge anomaly but this can be cancelled if the two fixed point planes
each support 8 chiral Fermions in the fundamental of U(N). Taking the low
energy limit leads to the worldsheet theory of N free heterotic strings whose
quantization induces an $E_8$ spacetime gauge symmetry on each fixed point
plane. Thus this paper presents a non-abelian worldvolume analogue of the
classic Horava-Witten analysis.
