Geronimo's friends sterling and Thunderhorn stayed to fight the monster.  So, Geronimo was all alone, however he kept on going and got into the witches' castle. He found Blossom in a prison. And Grim, Cackles' half brother freed her and heard her sang. Then suddenly, he turned to a fairy by Blossom's song! He helped Blossom and Geronimo. And met all Geronimo's friends again. When they went back to fairy land, Blossom and Grim (who changed his name to George) had a wedding. Then Geronimo woke up, it was all dream. He wrote this book and everyone loved it. I think this book is about 'Help' because George, Geronimo and Geronimo's friend helped Blossom. Helping people is very important you need to help people and Helping is very very nice.  

Helping is very important because it makes us happier and healthier. It makes us and the world better too.

​=> Another way: Your sentence is okay and this is another way of saying it.

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