In the two independent mol-ecules in the asymmetric unit of the title compound, C(13)H(9)N(3)O(2)S, the aza-tricyclo-trideca-penta-ene ring system is approximately planar with r.m.s. deviations of 0.022 and 0.033 Å. The urea unit connected to the fused rings is approximately perpendicular [dihedral angles = 82.4 (1) and 82.7 (1)°]. In the crystal, the mol-ecules associate by N-H⋯O hydrogen bonds, forming a chain running along the a axis. The crystal studied was a non-merohedral twin with a fractional contribution of 49.6 (1)% for the minor domain.