  We study the quasi-normal modes (QNMs) of a massless scalar perturbation to
the extremal M5-branes metric by using the exact WKB analysis. The exact WKB
analysis provides two exact QNMs conditions depending on the argument of the
complex frequency of the perturbation. The exact conditions show that the
discontinuity of the perturbative part of the QNMs leads the non-perturbative
part of themselves. We also find a new example of the Seiberg-Witten/gravity
correspondence, which helps us to compute the QNMs from our conditions.
