I enjoyed this book much more than the first in the series due to the added character development and the sex was much, much hotter (so important in an erotic novel).
Nature was not kind when designing the Zorns. Women had physical limitations to the amount of sex each could enjoy and the men had to literally cum or die, over and over and over again; a fact that almost made them extinct. Zorn society is much different than anything on Earth and dangerous whenever passions ignite. Argernon's passions, inflamed by rescuing Casey from danger drove him to bond with her. Now he'll never let her go.
Throughout the story Casey threw some magnificent temper tantrums, useful at letting others see her distress but useless in enforcing her will, especially with Algernon. When it really mattered, when it was do or die, she left the tantrums behind and attacked with everything she had, felling her opponents just as he did.
I have to wonder how the addition and interbreeding with all those sexually creative Earth women will change the society on Zorn.