Complex sentence: He gives her a salty cracker but no water; when Mona gets very thirsty, he lets her out and follows her to an underground cave spring she has discovered; there are also edible plant "sausages" growing in the water.
Split into simpler sentences: He gives her a salty cracker but no water; when Mona gets very thirsty, he lets her out and follows her to an underground spring she has discovered. As a bonus, there are also edible plant "sausages" growing in the water.