Hearts Below Series by Meredith Hart

The barrier was built to keep us safe. It’s killing us.I’ve devoted my life to protecting the kingdom I will someday rule, and all my research reveals there’s only one way to save us. The magical barrier that keeps our wicked enemies trapped in the Lands Below has to come down.But my desperate, covert attempt to bring down the barrier failed spectacularly. Now I’m trapped in the Lands Below, and at the mercy of the Captain of the Guard for the kingdom we defeated so long ago... moreThe barrier was built to keep us safe. It’s killing us.I’ve devoted my life to protecting the kingdom I will someday rule, and all my research reveals there’s only one way to save us. The magical barrier that keeps our wicked enemies trapped in the Lands Below has to come down.But my desperate, covert attempt to bring down the barrier failed spectacularly. Now I’m trapped in the Lands Below, and at the mercy of the Captain of the Guard for the kingdom we defeated so long ago.And I’m starting to think I shouldn’t have stabbed him. less

I’ll do anything to free my sister from King Grathgore’s court. Even if it takes me to the land of the monsters.In exchange for my sister’s freedom, I have to enter the terrifying Lands Below and stop the monsters' attempts to bring down the barrier keeping our two kingdoms separate. But stopping them ends up trapping me with a dangerous man named Aloserin in a place he calls the void, and Aloserin claims those who enter the void’s twisting forests and shifting paths rarely return... moreI’ll do anything to free my sister from King Grathgore’s court. Even if it takes me to the land of the monsters.In exchange for my sister’s freedom, I have to enter the terrifying Lands Below and stop the monsters' attempts to bring down the barrier keeping our two kingdoms separate. But stopping them ends up trapping me with a dangerous man named Aloserin in a place he calls the void, and Aloserin claims those who enter the void’s twisting forests and shifting paths rarely return.Still, I have an advantage those previous travelers did not: I can communicate with the shadow animals that so terrify Aloserin. Perhaps the two of us can survive long enough to find our way out.As long as Aloserin doesn’t discover that I’m the reason we’re both trapped here. less