In the future, fast food chains (often affiliated with schools of philosophy) run the world. Leonard his a professional Listener of Neetsa Pizza, answering calls to their complaints number through the night and following the scripts with the goal of getting the caller to convert, i.e. accept a coupon. Then one night the regular calls stop and he begins receiving calls from Marco Polo. So begins a journey that winds up involving time travel, Jewish mysticism, and awesome karate kicks.
A Highly Unlikely Scenario is wonderfully, delightfully bizarre. The overall feel of it reminded me of a combination of Mr. Penumbra's 24 Hour Book Store and the Thursday Next series, although aside from medieval name dropping (in the case of the former) and odd libraries (in the case of the latter) there isn't much concrete that it has in common with them. The pacing did feel just a bit strange, as if too much was happening and needing to be wrapped up quickly near the end, but this is Cantor's first novel so maybe that's something that will improve in future work.
Overall: A-