<P> The sixth season was announced on March 3, 2016, and premiered on September 25, 2016 . The characters must defend Storybrooke from the combined threat of Mr. Hyde and an unleashed Evil Queen and the mysterious fate of saviors leads to Emma learning about Aladdin (Deniz Akdeniz). The ongoing war between light and darkness ultimately leads to the arrival of the creator of the Dark Curse, the Black Fairy (Jaime Murray) as well as the final battle that was prophesied before the casting of the original curse . </P> <P> In May 2017, the series was renewed for a seventh season consisting of 22 episodes, which marks the beginning of a soft reboot . Years later after the Final Battle, Lucy (Alison Fernandez) arrives in the neighborhood of Hyperion Heights in Seattle, Washington with her Once Upon a Time book to find her father Henry Mills (Andrew J. West) who is needed by his family . Characters from the New Enchanted Forest were brought to Hyperion Heights under a new curse and are caught in a rising conflict involving Cinderella (Dania Ramirez) and Lady Tremaine (Gabrielle Anwar) whose dangerous history with Mother Gothel (Emma Booth) and the Coven of Eight are also revealed . The seventh season will serve as the final season of the series . </P> <Table> <Tr> <Th_colspan="2"> Season </Th> <Th_colspan="2"> Episodes </Th> <Th_colspan="2"> Originally aired </Th> <Th_colspan="4"> Nielsen ratings </Th> </Tr> <Tr> <Th> First aired </Th> <Th> Last aired </Th> <Th> Viewers (millions) </Th> <Th> Viewers rank </Th> <Th> 18--49 rating / share </Th> <Th> 18 - 49 rank </Th> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 22 </Td> <Td_colspan="1"> October 23, 2011 (2011 - 10 - 23) </Td> <Td> May 13, 2012 (2012 - 05 - 13) </Td> <Td> 11.71 </Td> <Td> 28 </Td> <Td> 4.1 / 10 </Td> <Td> 18 </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 22 </Td> <Td_colspan="1"> September 30, 2012 (2012 - 09 - 30) </Td> <Td> May 12, 2013 (2013 - 05 - 12) </Td> <Td> 10.24 </Td> <Td> 35 </Td> <Td> 3.6 / 9 </Td> <Td> 18 </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 22 </Td> <Td_colspan="1"> September 29, 2013 (2013 - 09 - 29) </Td> <Td> May 11, 2014 (2014 - 05 - 11) </Td> <Td> 9.38 </Td> <Td> 35 </Td> <Td> 3.3 / 8 </Td> <Td> 12 </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 22 </Td> <Td_colspan="1"> September 28, 2014 (2014 - 09 - 28) </Td> <Td> May 10, 2015 (2015 - 05 - 10) </Td> <Td> 8.98 </Td> <Td> 50 </Td> <Td> 3.2 / 7 </Td> <Td> 17 </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> 5 </Td> <Td_colspan="2"> 23 </Td> <Td_colspan="1"> September 27, 2015 (2015 - 09 - 27) </Td> <Td> May 15, 2016 (2016 - 05 - 15) </Td> <Td> 6.32 </Td> <Td> 69 </Td> <Td> 2.2 / 7 </Td> <Td> 34 </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> 6 </Td> <Td_colspan="2"> 22 </Td> <Td_colspan="1"> September 25, 2016 (2016 - 09 - 25) </Td> <Td> May 14, 2017 (2017 - 05 - 14) </Td> <Td> 4.39 </Td> <Td> 105 </Td> <Td> 1.5 / 5 </Td> <Td> 70 </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> 7 </Td> <Td_colspan="2"> 22 </Td> <Td_colspan="1"> October 6, 2017 (2017 - 10 - 06) </Td> <Td> May 18, 2018 (2018 - 05 - 18) </Td> <Td> TBA </Td> <Td> TBA </Td> <Td> TBA </Td> <Td> TBA </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Season </Th> <Th_colspan="2"> Episodes </Th> <Th_colspan="2"> Originally aired </Th> <Th_colspan="4"> Nielsen ratings </Th> </Tr>

How many season in once upon a time