  We study \textit{ab initio} a pyrochlore compound, CsW$_{2}$O$_{6}$, which
exhibits a yet unexplained metal-insulator transition. We find that (1) the
reported low-$T$ structure is likely inaccurate and the correct structure has a
twice larger cell; (2) the insulating phase is not of a Mott or dimer-singlet
nature, but a rare example of a 3D Peierls transition, with a simultaneous
condensation of three density waves; (3) spin-orbit interaction plays a crucial
role, forming well-nested bands. The high-$T$ (HT) phase, if stabilized, could
harbor a unique $e_{g}+ie_{g}$ superconducting state that breaks the time
reversal symmetry, but is not chiral. This state was predicted in 1999, but
never observed. We speculate about possible ways to stabilize the HT phase
while keeping the conditions for superconductivity.
