This is one of those cases where the title says it all, really! ^_^;
Because that's exactly what this dorama is: a "monologue between two people" ("futari"). The concept is simple yet interesting: instead of showing a dialogue between the two leads, they went with a double "interior monologue" that compelled the actresses to act silently (both Fukuhara Haruka and Yanagi Miki passed that "test" with flying colors, BTW!), then using the "voice over" to fully portray their feelings and thoughts! And, believe me, so much is going on in those pretty lil' heads of theirs! ^___^
The experiment was fully successfull, as far as I'm concerned: several scenes ended up being plainly hilarious (just take a look at the first 3 or 4 minutes, you'll get an idea!), the actresses, as already mentioned, did just great, the music is nice (particularly the ED song)...this might not be a full-fledged masterpiece, but it's still pretty original and very entertaining!