  M-theory on $AdS_7 \times S^4$ admits a description where the $AdS_7$ factor
is constructed as a timelike Hopf fibration over a non-compact three
dimensional complex projective space $\tilde{\mathbb{CP}}^3$. We consider the
worldvolume theory for M5-branes at a fixed $\tilde{\mathbb{CP}}^3$ radius
which, after reduction along the timelike fibre, is given by an
$\Omega$-deformed Yang-Mills theory with eight supercharges. Taking the radius
to infinity then induces a classical RG flow. We construct the fixed point
action which has an enhanced 24 supercharges and which can be understood as the
$(2,0)$ theory of M5-branes on flat space reduced along a compact null Killing
direction.
