  We make a comprehensive analysis on the phenomenology in the minimal version
of cascade seesaw for tiny neutrino mass. The seesaw induces at tree level a
neutrino mass operator at dimension nine, by introducing a quadruple scalar
$\Phi$ of hypercharge unity and a quintuple fermion $\Sigma$ of hypercharge
zero. We work in a framework that handles the complicated Yukawa couplings in a
nice way without losing generality. All mixing matrices are essentially
expressed in terms of the vacuum expectation value of the quadruple scalar
v_\Phi, a free complex parameter, and known neutrino parameters. We show that
the low-energy lepton flavor violating transitions of the charged leptons set
strong constraints on the free parameters. The constraints have a significant
impact on collider physics, and are incorporated in our signal analysis at the
LHC. We investigate the signatures of new particles by surveying all
potentially important channels. We find that the 4j2\ell^\pm signal is most
important for the detection of the scalars and the 2\ell^{\pm}2\ell^{\mp}2j,
3\ell^{\pm}\ell^{\mp}2j and 3\ell^{\pm}2\ell^{\mp}+\cancel{E_T} signals are
quite promising for the fermions.
