<Tr> <Td> 19 . </Td> <Td> "Closed City" </Td> <Td> 2: 18 </Td> </Tr> <Tr> <Td> 20 . </Td> <Td> "Helpless" </Td> <Td> 2: 26 </Td> </Tr> <Tr> <Td> 21 . </Td> <Td> "The Ruse" </Td> <Td> 2: 48 </Td> </Tr> <Tr> <Td> 22 . </Td> <Td> "Nightmares" </Td> <Td> 2: 20 </Td> </Tr>

What is the story of assassin's creed 3