"Venice in the year 1295. Amidst the Ascension Day festivities, Teresa Fiolaro, a woman who has longed for a child throughout her marriage, discovers an abandoned baby in a narrow canal.
She calls him Paolo.
Despite resistance from her husband, Marco, Teresa raises the child in their home among the glass-makers of Murano.
As Paolo grows up, his new parents realise that their son is short-sighted - but that this close vision gives him a strange and acute eye for distinguishing colour and tone. Such a talent is recognised by Simone Martini, a painter from Siena, who sends Paolo on a quest to find the perfect ultramarine blue, the colour of heaven - a journey that will take him across the world, through Persia, Afghanistan and China, in which he learns not only about colour but sight and distance, death and beauty, faith and love."