15-year-old Colin Campbell has grown up on his parents' farm, Ramore, on the beautiful Holy Loch; and soon he will be attending Glasgow University to study for the ministry. By chance he saves the life of a young man, Harry, the son of Sir Thomas Frankland. The two boys do not like each other, but the result is that Colin is occasionally invited to the Castle and falls in love with a witty, flirtatious girl, Matty, whose place in the social order is far above his.

We follow him through his adventures at University, and as a summer tutor at a great house, where once again he is thrown into Matty's company. Throughout this novel are long, metaphysical discussions between Colin and his even more serious friend Lauderdale regarding Christianity and the Kirk of Scotland. Later he makes a foolish decision in the hope of being near Matty.

Volume 2 changes both locale and characters when Colin must travel to Italy for his health, accompanied by Lauderdale. The second volume is almost a separate novel, a sequel to the first. While travelling, Colin and his friend find themselves emotionally caught up with a dying man and his sister, the Merediths, and set up house with them at Frascati near Rome. Again Colin will make a hasty decision which may affect his whole life.