In this talk, we introduce lightlike hypersurfaces in indefinite trans-Sasakian manifolds of type (alpha, beta), tangent to the structure vector field. The geometric configuration of such submanifolds is established. We characterize the normal bundle along any totally contact unbilical leaf of an integrable screen distribution. We finally prove that the geometry of any leaf of an integrable distribution is closely related to the geometry of a normal bundle and its image under phi.