Complex sentence: Homer travels back in time again to try to set things right; however, he accidentally kills a walking fish, and after returning to the present he finds Bart and Lisa are giants, narrowly avoiding being crushed by them.
Split into simpler sentences: Homer travels back in time again to try to set things right. However, he accidentally kills a walking fish, and after returning to the present he finds Bart and Lisa are giants, narrowly avoiding being crushed by them.