In the UK this is a trailer for Arrow episode after next (in other words we get the midseason premiere on Sky One next week and this is the episode after that) – 5.11 “Second Chances”. It does give quite a bit away about the midseason premiere so proceed with caution.
Oddly, although the episodes features the much publicised introduction of Lexa Doig as Talia al Ghul, she doesn’t appear to be in the trailer (unless we missed her)
Here’s the official synopsis: “TALIA AL GHUL TAKES OLIVER UNDER HER WING — In his quest to take down Kovar, Oliver (Stephen Amell) gets help from a surprising source – Talia al Ghul (Lexa Doig). However, when she reveals what she wants from him in exchange, Oliver isn’t sure he can accept her help. Felicity (Emily Bett Rickards) attempts to hack the NSA to help free Diggle (David Ramsey) but when her online efforts are flagged, she faces off against an unknown adversary. Meanwhile, Curtis (Echo Kellum) tells the team about a female vigilante, Tina Boland (Juliana Harkavay), he uncovered online who has been wreaking havoc all over the country.”