CAMBRIDGE — At the beginning of “The Lily’s Revenge,’’ a haughty figure named Time, played by Samantha Eggers with a cuckoo clock on her head and two smaller clocks on her shoulders, warns the audience that the performance they’re about to see will be “much longer than advertised. It is so long you may actually forget your name. . . . This play could very well last the rest of your life!’’

If truth-in-advertising regulations applied to stage dialogue, plenty of plays would begin with similar warnings. But you’re not likely to look at your own timepiece very often during the four hours and 20 minutes, including several intermissions, that it takes the American Repertory Theater production of “The Lily’s Revenge’’ to unfold at Oberon. There’s too much to see, hear, and generally absorb.