In December 2004, Doctor Maria Bennett, her husband Henry, and their three sons Lucas, Simon, and Thomas go on a Christmas holiday to Khao Lak, Thailand.

Communication facilities are scarce, but a German tourist named Karl, who has also been separated from his family, lends Henry his cell phone to contact his relatives.

The mistake is discovered when Lucas cannot identify any of the dead woman's jewelry and he is subsequently reunited with his mother, who had been moved to a private room in the ICU.

This meant Watts and Holland spent five weeks filming physically and psychologically demanding scenes in a massive water tank.

The website's consensus reads: "The screenplay isn't quite as powerful as the direction or the acting, but with such an astonishing real-life story at its center, The Impossible is never less than compelling.

[26] Roger Ebert of the Chicago Sun-Times gave a perfect four-star rating, praising the performances of Watts and McGregor, and the direction of Bayona.

[27] Deborah Young of The Hollywood Reporter gave a very positive review, praising the performances of the two leading stars, stating that "Watts packs a huge charge of emotion as the battered, ever-weakening Maria whose tears of pain and fear never appear fake or idealised.

McGregor, cut and streaked with excessive blood he seems too distraught to wash away, keeps the tension razor-sharp as he pursues his family in a vast, shattered landscape."

About the film she added, "The Impossible is one of the most emotionally realistic disaster movies in recent memory – and certainly one of the most frightening in its epic re-creation of the catastrophic 2004 Indian Ocean tsunami.

"[28] Justin Chang of Variety magazine gave a positive review, praising Bayona's directing and Sánchez's writing: "Collaborating again after their impressive 2007 debut feature, The Orphanage, Bayona and Sanchez get many things right here, starting with their decision to eschew a more panoramic view of the disaster to follow one family's journey from start to finish."

Holland, in his live-action bigscreen debut, is wonderful as a kind, somewhat short-tempered kid who still has plenty to learn, setting the tone for similarly heartrending turns by young Joslin and Pendergast.

He also praised the performances, stating that "as Maria, Watts is both brave and vulnerable, and her scenes with the young Lucas (the excellent Tom Holland) are among the film's best, with adult and child now unexpected equals, the mother humbled, the son rising to the challenge.

About the film, he added: "Part of the appeal of this affecting and powerful drama is that it puts the viewer right in the moment at every stage, using authentic locations and tsunami survivors to hammer home the reality of this tragedy.

"[31] According to The New York Times reviewer A. O. Scott, this narrowly-defined cinematic framing of the disaster through European and not Thai lenses represents "a troubling complacency and a lack of compassion in The Impossible", a movie which he found to be "less an examination of mass destruction than the tale of a spoiled holiday.

Rather than concentrating on the 'privileged white visitors', the film portrayed the profound sense of community and unity that I experienced in Thailand, with this family at the centre of it.