  Crystalline defects can modify quantum interactions in solids, causing
unintuitive, even favourable, properties such as quantum Hall effect or
superconducting vortex pinning. Here we present another example of this notion
- an unexpected unidirectional Kondo scattering in single crystals of 2H-NbS2.
This manifests as a pronounced low-temperature enhancement in the out-of-plane
resistivity and thermopower below 40 K, hidden for the in-plane charge
transport. The anomaly can be suppressed by the c-axis-oriented magnetic field,
but is unaffected by field applied along the planes. The magnetic moments
originate from layers of 1T-NbS2, which inevitably form during the growth,
undergoing a charge-density-wave reconstruction with each superlattice cell
(David-star-shaped cluster of Nb atoms) hosting a localised spin. Our results
demonstrate the unique and highly anisotropic response of a spontaneously
formed Kondo lattice heterostructure, intercalated in a layered conductor.
