Complex sentence: Finally realizing Joker isn't to be trusted, Venus defects to The Dynamic Duo's side and leads him to the Platter-Porium record shop and there, following a fierce battle with Joker's thugs, they find Leo Crustash.
Split into simpler sentences: Finally realizing Joker isn't to be trusted, Venus defects to The Dynamic Duo's side. She leads the duo to the Platter-Porium record shop and there, following a fierce battle with Joker's thugs, they find Leo Crustash.