Sentence 1: Eddie and his friends prepared dozens of water balloons. 
 Sentence 3: They waited quietly behind a bush for the girls to go by 
 Sentence 4:  They started throwing balloons as soon as they heard someone coming 
 Sentence 5:  Unfortunately it was not the girls but Eddie's mother walking by 
 Option 1: They were going to attack his big sister and her friends with them. 
 Option 2: They were going to attack his big brother and his friends with them.