Watch SAS: Red Notice (2021) online

SAS: Red Notice, directed by Magnus Martens, tells the story of Tom Buckingham (Sam Heughan), an agent of the British special air services, who leaves London for Paris with his fiancée, Dr. Sophie Hart (Hannah John-Kamen), to ask her to marry him. While the two are on the train that crosses the Channel Tunnel, a small armed group of terrorists, led by Grace Lewis (Ruby Rose), take control of the train and take all passengers hostage. She grace she claims to reveal some secrets of the British government, which she is in her possession, and to blow up the train if her ransom demands are not accepted.
Tom's presence on the train will prove to be the only hope for the passengers and Sophie to get out of that nightmare alive. Will the special forces agent, albeit unarmed, be able to foil the attack?