Alyssa and Jerome are cousins who have been sweethearts since childhood. Alyssa loved reading and often read poetry and literature with Jerome on the bench behind the garden. The two spent a long but carefree childhood in the countryside of Normandy. Love gradually took root among several boys and girls of the same age. At first, they secretly fell in love with each other, each hiding their secrets and worries, just like all teenagers who are just starting to fall in love. When they are deeply in love, their spirits merge and they want to become a better person for each other, completely unable to tolerate any imperfection. However, cousin Alyssa saw love eventually fall into an ordinary appearance in other people's ordinary marriages, and she had doubts about the end of love. What she wanted to pursue was eternal love, and she firmly believed that there is immortal love in the world, but the road to eternity is a narrow road, and the door to enter is a "narrow door" that "only a few people" can find. Immortality and eternal love require a lifetime and great efforts to achieve. This soul-stirring love was finally frozen forever as she wished, and remained in each other's hearts.