When the son of a billionaire couple is kidnapped during their messy divorce, the ransom is an ultimatum: one parent will get to take their son home ? the other must die.

I'd definitely read this. Good job.

I like this one. Conflict galore and implies that a great moral question will be addressed. The villain on the surface is the kidnapper, but the underlying current is human nature: will decency win out and the parents work together to solve the problem, or will their fight continue for dominance in winning the child - and therefore destroying the other parent. I like the possibilities.

the life-changing event and the jeopardy are clear. The heroes may be the parents. The villain is missing. It is odd that he does not demand money. The reader will guess that the kidnapper is forcing one parent to sacrifice himself to prove his love for the child. This is an obvious adaptation of King Solomon judging two mothers, both claiming that the one surviving baby is really her own.