When South Africa establishes a merchant navy of windships – hi-tech commercial sailing vessels that require young crews, or 'Greencaps' – Matt, Anil, Zosh and Marco enlist and attend university for a semester course as part of their training.  There they befriend Sarabi, a philosophy student and musician.  While Sarabi completes her degree, the sailors commence their voyages and the friends thread their way through adolescence prompted by the challenge to find a life worth living, against a nagging philosophical question: in a better world, could we flourish to the extent that no-one would regret being born?  The Greencaps seek adventure on the high seas while Sarabi contemplates her world and theirs from her lonely tower.