"Arrow" Season 2, Episode 9, "Three Ghosts," is the last from the hit The CW series in 2013. Fans knew there'll be cliffhangers. (Plural, yes.) And there were quite a few, including an origins story of another DC Comics hero, The Flash.

Spoiler alert: This feature recaps the highlights of Arrow Season 2, Episode 9, Three Ghosts. Read at your own risk. Scroll down to watch the Arrow 2x10 "Blast Radius" sneak preview promo.

Oliver Queen (Stephen Amell) thinks he's been visited by three ghosts in Arrow 2x09. But in truth, only two of them are really gone. The third ghost he sees is perhaps the person he loved the most among the three. Arrow fans loved him, too, so his "return" comes as such a holiday treat.

Shado (Celina Jade) is the first ghost to appear before Oliver. She tells him to stop fighting. Slade Wilson (Manu Bennett) appears next, insulting Oliver for his attempts at being a hero. The third ghost tells Oliver to "get up" and fight Cyrus Gold, a mercenary of Brother Blood (Kevin Alejandro).

A rather scruffy Tommy Merlyn (Colin Donnell) shows up in Arrow 2x09 to convince Oliver Queen he's not a murderer. Perhaps it Ollie's subconscious mind telling him to focus on the good he's done.

Arrow Season 2x09 'Three Ghosts' Review

Arrow Season 2x09, "Three Ghosts" is perhaps one of the best three episodes of the series, thus far. It helps that it got a rich lead from Arrow 2x08, "The Scientist." The episode has several excellent moments truly fitting for a mid-season finale. Roy Harper (Colton Haynes) was injected with the serum that changed Slade Wilson forever. And Slade, more appropriately, Deathstroke, is revealed to be the big boss of Brother Blood. And he wants vengeance against Oliver Queen. Almost every twenty frames of this episode carries something great for the viewers.

It looks like Grant Gustin may still be able to revisit Starling City as Barry Allen aka The Flash sometime in the future. He forms a bond with Felicity Smoak (Emily Bett Rickards) that is quite promising, to point out the least. Thanks to The Scientist, The Arrow gets a new, much easier to wear mask.

John Diggle (David Ramsey) also has some exciting stunts in the episode. The Olicity shippers of course got some moments, too -- even with The Flash around.

The next Arrow Season 2 episode airs January 15. Watch the Arrow 2x10 sneak preview promo below.

WATCH: 'Blast Radius' features Roy Harper with Super Strength

Olive Queen calls Thea Queen (actually, Merlyn) "Speedy." It doesn't happen often in the series, but when it does, the fans think of Roy Harper. In the next new episode of Arrow, Harper is shown with some serious super strength. Will he stay on Arrow's side? More important, does he remember seeing Oliver Queen when he resurfaced from after life?

Arrow Season 2, Episode 9 promises a more exciting, more action-packed series in 2014. The Black Canary (Caity Lotz) is bound to resurface. A face-off between Slade Wilson and Oliver Queen is about to unfold. And then there's Malcolm Merlyn (John Barrowman), who Oliver thinks is dead. More DC Comics heroes and villains are coming or evolving. Fans would want the holiday weeks to speed by.

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