William tries to save Star City from destruction in the TV show Arrow .
The season features flash-forwards twenty years into the future to Oliver 's son William 's adulthood , where he seeks out an aged Roy Harper on Lian Yu , and they discover an instruction made by Oliver and Felicity at some point , and discovers more secrets of their legacies , including William 's previously unknown half-sister Mia , while trying to save Star City from being destroyed.
Arrow -LRB-TV series-RRB-