We study a secluded dark-matter scenario in which the smallness of laboratory signals is linked to the origin of neutrino masses. In the four-dimensional theory, the dark sector contains a hidden scalar, a fermionic dark-matter particle, and heavy Majorana neutrinos. The same heavy-neutrino sector that generates light neutrino masses via the seesaw mechanism also induces the Higgs–dark scalar portal at one loop. This portal is tied to the small observed neutrino masses, naturally leading to very small Higgs–singlet mixing and suppressed signals in direct-detection and collider experiments. We then provide a geometric origin for the boundary condition of the tree level portal coupling being zero (_{UV}) = 0 via a five-dimensional sequestered setup. In this construction, the Standard Model fields and the hidden sector are localized on different branes, with sterile neutrinos propagating in the bulk. Five-dimensional locality forbids a fundamental local tree-level Higgs–dark-scalar contact interaction, while heavy-neutrino loops induce a small residual portal coupling. The main phenomenological parameter controlling the viability of the model is the heavy-neutrino mass scale: direct detection bounds it from above, while Big Bang nucleosynthesis bounds it from below through the requirement that the hidden scalar decays sufficiently early. Depending on the amount of five-dimensional sequestering, the viable region can span heavy-neutrino masses from the multi-TeV scale to the PeV scale, or even higher.