  We describe progress in using the field theory of tensionless strings to
arrive at a Lagrangian for the six-dimensional $\mathcal N=(2,0)$ conformal
theory. We construct the free part of the theory and propose an ansatz for the
cubic vertex in light-cone superspace. By requiring closure of the $(2,0)$
supersymmetry algebra, we fix the cubic vertex up to two parameters.
