  In contrast to almost all anisotropic superconductors, the upper critical
field of URu$_{2}$Si$_{2}$ is larger when the field is oriented along the less
conducting direction. We present a study of resistivity and Seebeck coefficient
extended down to sub-Kelvin temperature range uncovering a singular case of
anisotropy. When the current is injected along the c-axis URu$_{2}$Si$_{2}$
behaves as a low-density Fermi liquid. When it flows along the a-axis, even in
presence of a large field, resistivity remains T-linear down to T$_{c}$ and the
Seebeck coefficient undergoes a sign change at very low temperatures. We
conclude that the characteristic energy scale is anisotropic and vanishingly
small in the basal plane.
