The New Teen Titans #34

ENDINGS... AND BEGINNINGS!
The Titans surprise Terra with a birthday party, but she remains disgruntled that they have refused to share their secret identities with her since she joined the team.  Robin becomes angry with Adrian Chase when the district attorney uses Robin's status as a legal deputy to raid Anthony Scarapelli's home in a possibly illegal manner.  Kid Flash decides to leave the Titans to concentrate on college, Donna accepts Terry's proposal, and Cyborg remains unhappy at having learned that Sarah is engaged, unaware that Mark Wright had misrepresented himself as her fiance.  All of these developments are put aside, however, when the Terminator returns to challenge the team, and Terra determines to prove her worth by battling him alone.  Although the other Titans join the fight, and although the villain ultimately escapes, Terra is unquestionably the heroine of the battle, and the Titans decide to share their secrets with her at their next meeting.  That night, Terra meets with the Terminator at her apartment.  Unsuspected by the Titans, she has been the Terminator's partner from the beginning, planted in the group as a double agent to betray them.  Meanwhile, moments after Robin leaves Adrian Chase's home, the district attorney's apartment building is rocked by an explosion.
4th appearance of Deathstroke, the Terminator.
NOTE: The story continues in The New Teen Titans Annual #2.