Simplify the following text for a Grade 9 native English-speaking person.
Original: Overhearing Atlas ' words , Dr. Tenenbaum , the creator of the Little Sisters , intercepts Jack , and urges him to save the Little Sisters instead , giving him a plasmid that will displace the embedded sea slugs in each Sister .
Simplified: Overhearing Atlas ' words , Dr. Tenenbaum intercepts Jack , and urges him to save the Little Sisters instead , giving him a plasmid that will displace the embedded sea slugs in each Sister .