It's excruciating to imagine a family being violently separated during a cataclysmic event, and almost as difficult to fathom how they could find their way back together.
The Impossible ( * * * ½ out of four; rated PG-13; opening Friday nationwide) embraces both of those emotionally pitched scenarios, and its title also might reflect the momentous task of approximating the calamity for the screen.
In any case, this tense and deeply moving film, based on a true story that occurred during the 2004 Indian Ocean tsunami, achieves its goals on all counts.
The Bennett family - Maria (Naomi Watts), Henry (Ewan McGregor) and their three sons - are British expats vacationing in a resort in Thailand when the tsunami hits.
Ninety-eight-foot-tall waves crash over their hotel just as the two youngest Bennett sons Simon (Oaklee Pendergast) and Thomas (Samuel Joslin) are frolicking in the pool with their father. Older son Lucas (Tom Holland) and his mother are standing poolside.
Director Juan Antonio Bayona's jaw-dropping special effects are astoundingly realistic and truly terrifying. The impact of a 10-minute sequence of devastation is all the more astonishing because Bayona's film is no big-budget blockbuster, and this is only the second effort from the Spanish filmmaker.
The scenes in which Maria and Lucas battle perilous currents to reach each other, then cling together in a tree for safety - along with a lost toddler - are especially wrenching. But quieter moments of anguish and hope leave just as lasting an impression.
Holland does a wonderful job as young Lucas, who is determined to stay close to his mother but also wants to help relieve the suffering of others. We feel his anxiety and terror and lament the terrible burden placed on him as he is thrust into adulthood.
Watts is pitch-perfect in a role that requires her to have the steely aplomb of the physician she has trained to be and the frayed urgency of a mother fighting to save her children. McGregor also gives a fiercely credible performance as a father struggling between caring for his two young sons and searching for his wife and oldest son. Holland, Watts and McGregor invest their parts with uncommon conviction.
This is a tale not only of epic disaster but also of resilience. The Impossible is a nimbly acted drama that is at once a stellar visual achievement and a life-affirming story of familial love and courage.