The symmetric orbifold of T^4, Sym_N(T4), is dual to tensionless string theory on AdS3 x S3 x T4 with one unit of NS-NS flux. In this talk I will study the deformation of the symmetric orbifold theory that corresponds to switching on R-R flux (and hence the string tension) in the bulk. Working in the planar large N limit as well as the limit of large twist, I will explain how the deformation can be explicitly described, in the symmetric orbifold, by a dynamical spin chain that seems to be integrable. Among other things, this allows us to give explicit predictions about the anomalous conformal dimensions of all multi-magnon states.