  We find an N=1 gauge theory that flows to the rank-one N=2 superconformal
field theory with $E_7$ flavor symmetry. We first obtain a Lagrangian
description for the $R_{0, N}$ theory, which appears in the S-dual description
of the SU(N) gauge theory with 2N fundamental hypermultiplets. This is a
straightforward generalization of the proposed Lagrangian description for the
$E_6$ theory. The $E_7$ theory is then obtained via partial Higgsing of the
$R_{0, 4}$ theory. From this Lagrangian description, we compute the full
superconformal index. We also consider twisted dimensional reduction on $S^2$
to obtain N=(0, 4) theory for the $E_7$ one instanton string and compute its
elliptic genus.
