Complex sentence: Héctor attempts to return Miguel to his relatives, but Miguel escapes and infiltrates Ernesto's mansion, learning along the way that an old friendship between the two had soured before Héctor's death.
Split into simpler sentences: Héctor attempts to return Miguel to his relatives, but Miguel escapes and infiltrates Ernesto's mansion. Along the way, he discovers that an old friendship between the two had soured before Héctor's death.