My favorite TV shows are serialized dramas, and "Once Upon a Time" is one of the best of those. It's a clever twist on childhood fairy tales, with famous characters like Snow White, Red Riding Hood, the Evil Queen, and others being real people who, due to an evil curse, have been transported from the Enchanted Forest to a small town in Maine.
Beginning in season 3, "OUaT" transitioned to a fall/spring split half season structure. In season 4, the fall arc built on the narrative from the movie "Frozen" (both that and this show are produced by Disney), and the spring arc pitted our main characters against three "queens of darkness."
Season 4 wasn't the strongest one in the series history, but it still delivered consistent entertainment with multiple strong female characters. Indeed, one of the interesting things about this show is that nearly all of the male characters seem bland, while the female ones (Snow, Emma, Regina) really drive things. If you are into the Bechdel test, this show passes easily.