<P> This is a list of episodes of the American animated television series Ben 10: Alien Force . The series was created by team Man of Action (a group consisting of Duncan Rouleau, Joe Casey, Joe Kelly, and Steven T. Seagle), and produced by Cartoon Network Studios . It takes place five years after the 2005 television series Ben 10 and takes a darker turn than its predecessor . Ben 10: Alien Force was followed by the direct 2010 sequel series Ben 10: Ultimate Alien . </P> <Table> <Tr> <Th_colspan="2"> Season </Th> <Th_colspan="2"> Episodes </Th> <Th_colspan="2"> Originally aired </Th> </Tr> <Tr> <Th> First aired </Th> <Th> Last aired </Th> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 13 </Td> <Td_colspan="1"> April 18, 2008 (2008 - 04 - 18) </Td> <Td> August 31, 2008 (2008 - 08 - 31) </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 13 </Td> <Td_colspan="1"> October 10, 2008 (2008 - 10 - 10) </Td> <Td> March 27, 2009 (2009 - 03 - 27) </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 20 </Td> <Td_colspan="1"> September 11, 2009 (2009 - 09 - 11) </Td> <Td> March 26, 2010 (2010 - 03 - 26) </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="3"> Movie </Td> <Td_colspan="2"> November 25, 2009 (2009 - 11 - 25) </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Season </Th> <Th_colspan="2"> Episodes </Th> <Th_colspan="2"> Originally aired </Th> </Tr>

How many episodes are in ben 10 alien force season 1