The resonant substructure of B 0 s →D 0 K − π þ decays is studied with the Dalitz plot analysis technique. The study is based on a data sample corresponding to an integrated luminosity of 3.0 fb −1 of pp collision data recorded by LHCb. A structure at mðD 0 K − Þ ≈ 2.86 GeV=c 2 is found to be an admixture of spin-1 and spin-3 resonances. The masses and widths of these states and of the D Ã s2 ð2573Þ − meson are measured, as are the complex amplitudes and fit fractions for all theD 0 K − and K − π þ components included in the amplitude model. In addition, the D Ã s2 ð2573Þ − resonance is confirmed to be spin 2.