Writers block - please help me

Okay so the basic layout of my story is sooooooooortt of like Romeo and Juliet, but let me explain.
There is the light realm, fire realm, water realm, air realm and earth realm (aka earth) and the people from each realm have different powers (fire realm can bring people back to life, air realm can create tornados, etc). The mc is the heir to the light realm throne but only finds this out when she is seventeen (she lives on earth). A guy from the fire realm is resurrected because although he committed a crime and was sentenced to death, his expertise was needed to stop the heir to the light realm throne claiming the crown.
So the part I need help with is coming up with what the fire realm dude’s “helpful expertise” is and how he plans to stop her. And how they encounter on earth and what not.
I feel it’s got potential but I just have so little creativity that I don’t know how to do the idea justice.

I guess first you need to know what’s the capability of the light realm heir then that’s about when you can think of what skill can oppose to what she can do.