Thick and Thin follows life-long friends when their world is hit by a bombshell As students, Marianne Dillon and Clare McMahon become instant and unlikely friends. Marianne's generosity and Clare's steadfastness are the glue of a friendship that sees them through twenty-five years of love and loss, successes and disappointments, marriage and motherhood. But when a life-altering crisis hits their relationship, a crisis that involves their husbands, children and indeed the lives they have created, the crack that was there all along tears them apart.