Gin Bianco is the assassin named the Spider. We know her, we love her. 
 She is very protective of her "family" and when Jo-Jo and Sophia are threatened she will do whatever she needs to save them. Anyone against her family is her enemy and she will torture and kill whomever messes with them. 
 The evil in this book are the siblings Grime and Hazel, they are fire elementals. They have a past with Sophia and Jo-Jo. When Sophia is kidnapped it is up to Gin to save her. She is not alone this time, she gets the help of Owen. 
 Finally, Owen is back. The character we fell in love with and who was missing from the last two books. He supports Gin in every decision. This book was much better relationship wise. I liked that we get more info on Sophia's past. Felt bad for her. I hope she finds peace and happiness soon. 
 I was very happy with Heart of Venom. I love how cool Gin is and can't wait to read more about her adventures. 
 4/5 Fangs 
 cross posted at my blog http://mrsleifs.blogspot.com