Peter (Hugh Jackman) and Beth (Vanessa Kirby) are euphoric after the birth of their first child. Their little family is about to unexpectedly expand, however, with the arrival of Nicholas (Zen McGrath), Peter’s adolescent son from his previous marriage to Kate (Laura Dern). Nicholas suffers from severe depression, which manifests in uncontrollable tears, withdrawal from social activities, and worse. It has become too painful for Kate, who has run out of options and hopes that Nicholas’s interest in his new sibling will lift his spirits and prevent him from tumbling headlong back into despair.