String theory on {\rm AdS}_3 \times {\rm S}^3 \times {\rm S}^3 \times {\rm S}^1 with pure NS-NS flux and minimal flux through one of the two {\rm S}^3's is studied from a world-sheet perspective. It is shown that the spacetime spectrum, as well as the algebra of spectrum generating operators, matches precisely that of the symmetric orbifold of {\rm S}^3\times \mathrm{S}^1 in the large N limit. This gives strong support for the proposal that these two descriptions are exactly dual to one another.
