Time and place of action – XVI century, Scotland under James V.
Elena comes across the King, who presents himself under the name of Uberto and immediately falls in love with her. The girl takes him for a hunter, who has lost his way, and offers him shelter. While talking with her, the King learns that Elena is the daughter of the enemy of the crown Douglas, who long time ago was his royal tutor and teacher. It turns out that the beautiful stranger is engaged to Rodrigo – the chief of the rebel Highlander clans. After the King has left, appears Malcolm who has fallen in love with Elena. He has decided to join the rebels and win his beloved, even if his rival is the strongest man in the world. Shortly after, Malcolm overhears the conversation between Elena and Douglas, who discuss the girl’s marriage with Rodrigo. Elena opposes, but her father declares that daughters must obey their parents. Malcolm and Elena, however, secretly take a vow to remain faithful to each other.
In the next scene, the Highlanders welcome Rodrigo, who pledges to lead them to victory, but expresses also impatience to see his future bride. The Scots assure him that the military victory, as well as the hand of the beloved woman will be his. Douglas arrives and cordially greets Rodrigo. The young leader of the rebels expresses again his ardent desire to see Elena. Here she comes and Rodrigo is ready to unleash all his passion. Douglas, concerned by the fact that his daughter does not respond at all to the feelings of the fiancé, approved by him, explains to Rodrigo that the girl is too shy. But when Malcolm, together with the men from his clan, joins the rebels, Rodrigo perceives the connection between the young warrior and his fiancée. Abruptly, Serano enters and reports that the King’s army has attacked the rebels, and in the same time a strange omen has appeared in the sky. A chorus of bards sings the praise of honour and glory, while Rodrigo, Malcolm and the Highlanders prepare themselves for the crucial battle.
King James knows that the battle between his army and the Highlanders will be fierce and he has come to find Elena with the hope to protect her. Still under the name Uberto, he presents himself for a quite ordinary man and declares his love, but he is shaken, when she tells him that her heart belongs to another man. Nevertheless, the pretended Uberto gives her a special ring he says the King gave him, and emphasizes that it will see her through any danger. And just as King James prepares to leave, Rodrigo rushes in. He has become witness of the end of the conversation and orders his people to kill the stranger. Elena intercedes for Uberto and then Rodrigo and the King decide to duel each other. The two exit to find an appropriate secluded place for the skirmish, and the girl follows them, trying to calm them down.
In the next scene it becomes clear that the rebels suffer heavy losses in the war with the King’s army. Malcolm learns that Elena has gone in search of her father, who is on a peace mission to the palace. Desperate that he has maybe lost his beloved, Malcolm seeks his own death, but after a while he is confronted by Highlanders from the clans who announce that Rodrigo has been slain in a battle and the rebels face total defeat. Malcolm leaves for the palace, determined to rescue Elena – even at the price of his own life.
The final scene of the opera takes place in the elegant royal palace of James V. Douglas begs his former student to have pity not only on him, but on his daughter and his brothers-in-arms too. The King refuses and orders him imprisoned, but actually James is saddened by the fact that he is forced to show severity towards his favourite tutor. Meanwhile, Elena arrives in the palace and shows the ring from the King, in order to save the lives of her father, her beloved Malcolm and Rodrigo (of whose death she is unaware). Suddenly, from the next room is heard the voice of “Uberto”, singing about his love for her. Thrilled, Elena hopes the pretended Uberto would help her at the meeting with the King. The two enter the throne room, but the girl is quite surprised by the courtiers' behaviour. Finally, she realizes that “Uberto” and the King are one and the same person! James V, moved by his love for Elena, declares that he will forgive Douglas, but, however, he considers to condemn Malcolm. Finally, he yields and frees his young rival too. Elena and Malcolm are together at last. In her final rondo, Elena expresses her great happiness because of the salvation of her dearest people, and all the rest rejoice, because peace has returned to Scotland.