Part of a four issue crossover mini series. The Next book to read is: The issues before was WildC.A.T.S. / X-Men: Modern Age
This whole collection has been collected in WildC.A.T.S / X-Men
NOTE: Indicia titled as "WildC.A.T.S/X-Men: The Dark Age".
— Description from Comic Vine community (comicvine.gamespot.com · https://comicvine.gamespot.com/wildcatsx-men-the-dark-age/4050-19017/).
