Complex sentence: When they are finished, Macavity returns disguised as Old Deuteronomy, but when Demeter blows his cover, Macavity now ends up fighting with Munkustrap and Alonzo.
Split into simpler sentences: When they are finished, Macavity returns disguised as Old Deuteronomy. When Demeter blows his cover, Macavity now ends up fighting with Munkustrap and Alonzo.