The propagation of surface-plasmon-polariton (SPP) waves guided by a metallic defect layer in a sculptured nematic thin film (SNTF) was studied theoretically. The defect layer was taken to be deposited by electron-beam evaporation, and the SNTF was taken to be made by similarly evaporating titanium oxide. We found that when the defect layer's thickness is much greater than the penetration depth, SPP waves propagate guided by the two metal/SNTF interfaces independently. As the defect layer's thickness is reduced, coupling of the two interfaces results in new SPP waves. The smaller is the thickness of the metallic defect layer, the stronger is the coupling effect.