The Libation Bearers is the second play in the Ancient Greek tragic trilogy, The Oresteia, by Aeschylus. Electra and Orestes meet on the grave of their father, King Agamemnon, who was killed by their mother, Clytemnestra. Servants have been pouring libations on the grave to appease Agamemnon's spirit after Clytemnestra dreamt that she gave birth to a snake which was now drinking milk and blood from her breast. The siblings enter the palace and kill Clytemnestra and her husband, Aegisthus, before being chased away by the Erinyes (furies).
Boasting the largest collection of book summaries, BookRags is the best option for titles you can't find elsewhere. They offer all of the basics (quotes, chapter summary, characters, historical context, literary criticism) but also walk through a few major topics that recur throughout the book, which can be particularly useful for essay writing.
The most popular website for book notes. SparkNotes was created by students for students, and their summaries are accessible and extremely well-written. Besides the usual plot overview, chapter summaries, and character analysis, SparkNotes differentiates itself with a section discussing themes, motifs, and symbols.
You won't get any frills with GradeSaver -- just the content you expect. Their study guides include a full plot summary, themes and character analysis, study questions, and the e-text of the book. One hidden gem is their collection of literature essays, but you'll have to pay for it.
If you're bored by traditional book notes, try Shmoop! They write their summaries in an approachable, entertaining style. Their comprehensive offering includes chapter by chapter summaries, themes, quotes, character analysis, study quizzes, and even flash cards and infographics.