The robotic alien hive-mind known as has launched a full-scale attack on Earth. While Martian Manhunter (J'onn J'onzz) warns of the threat, Batman initially tries to stop the invasion alone to protect Batgirl and Robin from danger.
Encouraged by Alfred, Batgirl and Robin disobey Batman’s orders to stay behind and join the fight, eventually holding off robots while Batman hacks the system. [S4E13] The Joining: Part 2
The episode ends with Batman joining J'onn on the Watchtower space station, where he meets other heroes: Green Lantern, The Flash, Hawkman, and Green Arrow . The robotic alien hive-mind known as has launched
" The Joining: Part 2 " is the season finale of The Batman (2004) Season 4, originally airing on May 5, 2007. The episode concludes the high-stakes alien invasion arc and marks Batman's official transition from a solo vigilante to a member of the Justice League. The episode ends with Batman joining J'onn on