<P> The second season of Pretty Little Liars, based on the books of the same name by Sara Shepard, premiered on June 14, 2011 and concluded on March 19, 2012 on ABC Family . On January 10, 2011, ABC Family renewed the series for a second season . The season premiere brought in 3.68 million viewers, which was higher than the season 1 premiere . The Halloween special aired on October 19, 2011, drawing 2.5 million total viewers . The second half of season 2 premiered on January 2, 2012 . </P> <P> The second season continues from the season finale of the previous season, in which Ian Thomas (Ryan Merriman), Spencer's brother - in - law, is presumed to have been killed in an incident at the top of a bell tower but is also accused of murdering Alison . Following the incident, the girls are forced to keep their friendship a secret and to attend therapy sessions, making them feel more alone than ever . The girls found themselves unable to open up to their therapist, Dr. Sullivan, about' A' . Spencer begins suspecting that Ian is alive when Melissa receives messages from her phone and lies about her whereabouts . When they follow Melissa, they discover Ian's dead body, along with a suicide note, admitting that he killed Alison, however the girls later discover that Ian's suicide note was A-orchestraed and that it wasn't Ian who killed Alison . They also discover that Garrett cannot be trusted after finding out his connection to Jenna . Eventually the girls confess to Dr. Sullivan about' A' . Just when Dr. Sullivan was able to identify who' A' was, she disappears . Later' A' reveals that she has Dr. Sullivan and made the girls think she was in danger, however this is revealed to be a trap, as the girls were arrested for tampering with the weapon used to kill Alison . </P> <P> The second half deals with the girls being more determined to find out who' A' is . They set up a plan that tricked' A' . The plan had moderate success as the girls were able to steal A's phone . The girls (except Hanna) enlists Caleb's help on hacking to A's phone; however, A tries to shut down the phone, but before A shuts the phone, they were able to discover some clues . Their investigation later leads them to Lost Woods resort, locating A's lair in one of the rooms . Meanwhile, Garrett is arrested for Alison's murder after Jenna hands the ripped page 5 of Alison's autopsy report to the police . After finding more clues, Spencer discovers that' A' may be her sister, Melissa, but when she and Mona head to A's lair, she finds clues that lead to the identity of' A': Mona . Mona is admitted to Radley, and Dr. Sullivan returns after revealing it was Mona who threatened her . Later Maya is found dead near Emily's house, devastating Emily . In Radley, Mona is visited by a woman in a red coat and Mona reports back to the figure, revealing that the A-Team has a new leader . </P> <Table> <Tr> <Td> <H3> Main cast (edit) </H3> <Ul> <Li> Troian Bellisario as Spencer Hastings </Li> <Li> Ashley Benson as Hanna Marin </Li> <Li> Holly Marie Combs as Ella Montgomery </Li> <Li> Lucy Hale as Aria Montgomery </Li> <Li> Ian Harding as Ezra Fitz </Li> <Li> Bianca Lawson as Maya St. Germain </Li> <Li> Laura Leighton as Ashley Marin </Li> <Li> Chad Lowe as Byron Montgomery </Li> <Li> Shay Mitchell as Emily Fields </Li> <Li> Sasha Pieterse as Alison DiLaurentis </Li> </Ul> </Td> <Td> <H3> Recurring cast (edit) </H3> <Ul> <Li> Tyler Blackburn as Caleb Rivers </Li> <Li> Janel Parrish as Mona Vanderwaal </Li> <Li> Keegan Allen as Toby Cavanaugh </Li> <Li> Tammin Sursok as Jenna Marshall </Li> <Li> Yani Gellman as Garrett Reynolds </Li> <Li> Drew Van Acker as Jason DiLaurentis </Li> <Li> Torrey DeVitto as Melissa Hastings </Li> <Li> Brendan Robinson as Lucas Gottesman </Li> <Li> Cody Allen Christian as Mike Montgomery </Li> <Li> Nolan North as Peter Hastings </Li> <Li> Roark Critchlow as Tom Marin </Li> <Li> Brant Daugherty as Noel Kahn </Li> <Li> Nia Peeples as Pam Fields </Li> <Li> Julian Morris as Wren Kingston </Li> <Li> Lesley Fera as _́ Veronica Hastings </Li> <Li> Annabeth Gish as Anne Sullivan </Li> <Li> Shane Coffey as Holden Strauss </Li> <Li> Bryce Johnson as Darren Wilden </Li> <Li> Paloma Guzmán as Jackie Molina </Li> <Li> Natalie Hall as Kate Randall </Li> </Ul> </Td> <Td> <H3> Guest cast (edit) </H3> <Ul> <Li> Ryan Merriman as Ian Thomas </Li> <Li> Claire Holt as Samara Cook </Li> <Li> Heather Mazur as Tom Marin </Li> <Li> Jim Titus as Barry Maple </Li> <Li> Eric Steinberg as Wayne Fields </Li> <Li> Lindsey Shaw as Paige McCullers </Li> <Li> Lachlan Buchanan as Duncan Albert </Li> <Li> Amanda Schull as Meredith Sorenson </Li> <Li> Andrea Parker as Jessica DiLaurentis </Li> <Li> Betty Buckley as Regina Marin </Li> <Li> Tilky Jones as Logan Reed </Li> <Li> Anthony Tyler Quinn as Ron </Li> </Ul> </Td> </Tr> </Table>

Who dies at the end of season 2 pretty little liars