By Rebecca Thomas BBC News Online entertainment staff

If the measure of good dramatic entertainment is the breadth and depth of the feelings it explores and inspires then Monster's Ball ranks among the very best.

Nerve-endings are left tingling as everything from fear and hatred to love and peace is portrayed in this intense, raw but infinitely humane drama.

And though the characters and their scenarios which flesh out the story are familiar, from poor single mothers to racist prison guards, the script in which they are presented is both unpredictable and courageous.

Death row

At the heart of the story, set in the southern US state of Georgia, are two diametrically opposed people.

Leticia Musgrove, played by Halle Berry, is the impoverished wife of a death row convict, struggling to cope with mounting debts and an overeating and emotionally fragile son.

Meanwhile, Hank Grotowski, played by Billy Bob Thornton, is a stony-faced guard on that same death row, who finally takes Leticia's husband to the electric chair.

The acting is excellent but the real star is the screenplay

Meticulous and cold in his approach, he shows himself every inch the racist bigot he has been brought up to be by his now ailing former prison guard father Buck, played by Peter Boyle.

Though seemingly unlikely to ever darken each other's door, Hank and Leticia are brought together by sudden tragedy in both their lives, unaware of the connection between them through Leticia's husband.

Hank, compelled to re-assess his life and confront his loneliness and self-hatred, is drawn to Leticia by a need for friendship and intimacy. Leticia craves love and protection from her hand-to-mouth existence.

Their desperation explodes in a graphic sex scene rarely seen in American films but ultimately it is the poignancy of the gentle love that grows between them that remains etched on the mind.

Soul-baring

To perform this story, Berry and Thornton agreed to be paid much less than they would usually for a film.

But it is not hard to understand why they were so attracted by the script which, though sparse in dialogue, allows its actors to mine their talents and lay themselves open to a rare degree.

Berry's soul-baring as Leticia is outstanding as she veers from weary, bullying mother to vulnerable, child-like lover.

But if Berry's performance rightly won her an Oscar, so too should that of Thornton, who elicits extraordinary sympathy as the craggy remorse-ridden Hank.

And even Boyle's cameo role of Hank's loathsome father is worthy of praise.

Yet, perhaps the real star of Monster's Ball is the screenplay which, though seemingly presenting a set of cliches and patronising lessons in morality, unfolds with refreshing subtlety and challenges expectations.