Warning: the following contains spoilers for Titans episode 9, 'Hank and Dawn'.
'Hank and Dawn' - the latest episode of Titans - ended with the revelation that the vigilantes Hawk and Dove must find the second Robin, Jason Todd, though the precise reasons why are murky at best. This surprising twist was the confusing capstone to an episode that many felt paradoxically managed to be one of the strongest of the series to date, while still seemingly having nothing to do with the overall series' narrative.
Fighting crime under the names Hawk and Dove, Hank Hall and Dawn Granger were introduced in the second episode of Titans, 'Hawk and Dove'. Old friends of Dick Grayson from his days as Batman's partner, the former Robin sought them out when he needed a safe place to hide runaway teen Rachel Roth while he investigated her mother's murder. The three heroes were ambushed by a strange family of assassins, resulting in a battle that ended with Dove in a coma and Rachel abducted. This is where the series left Hawk and Dove for a number of episodes until the narrative picks up with 'Hank and Dawn'. This confused many, as the previous episode, 'Donna Troy' ended with a cliffhanger that goes (seemingly) unaddressed by "Hank and Dawn."
Most of "Hank and Dawn" is devoted to twin flashbacks, apparently being dreamed by the doped-up Hank Hall and the comatose Dawn Granger. Hank recalls his youth and how he and his younger brother, Don, became vigilantes who targeted pedophiles. Dawn dreams of how she met Hank and was drawn into his world. Both dreams are intercut with random images of Rachel Roth in reflective surfaces, crying out to both heroes asking for help. The episode ends with Dawn waking from her coma and telling Hank that Rachel needs help and that they need to find Jason Todd.
Apparently this ties into the cliffhanger from 'Donna Troy' which ended with Rachel being strangled by Kory Anders as Dick Grayson and Donna Troy rushed to the farm where Rachel and Kory were hiding, having discovered that the amnesiac Kory may have been recruited to kill Rachel before she lost her memory. Certainly Rachel is in danger, but it is unclear how her psychically reaching out to Hank and Dawn could save her, given that she was in Killdeer, Ohio and they were in Washington D.C. It is even more uncertain what Jason Todd, the new Robin, could possibly do to help Rachel, as he operates out of Gotham City and Hank and Dawn have never met him before.
Looking back to the classic New Teen Titans comics by Marv Wolfman and George Perez offers one possible explanation. In the comics where Rachel Roth's character was first introduced as the magical heroine Raven, she formed a new Teen Titans team by appearing to the people she needed to recruit in their dreams and telling them what they needed to do to avert a future crisis. This explains Rachel's presence in the dream flashbacks but doesn't explain precisely why she contacted Hank and Dawn and why she needs Jason Todd.
One possibility to consider is that we don't know for certain that the scene in which Dawn wakes in the hospital is taking place at the same time that Rachel is being attacked by Kory. Given that Rachel's powers in the comics include precognition and a soul self that can act independently of her, it is entirely possible that Rachel's other self saw what was coming and pre-emptively acted to make sure she'd have people ready to save Rachel at the precise moment they were needed. This seems likely given that Rachel is still learning precisely what she can do with her magical powers and she'd never shown any sign of being able to communicate telepathically across several hundred miles before now. Hopefully the next episode of Titans will offer an adequate explanation beyond bringing together all eight heroes the series has introduced so far for one final season-ending battle.