Combining the whimsical science fiction ofDoctor Whowith the Victorian sentimentality of Dickens'sA Christmas Carolmay seem silly at first glance, but it turns out they're a perfect fit--A Christmas Carolis, after all, already a time-travel story. On a distant planet, the Doctor (Matt Smith) confronts a miserly curmudgeon named Kazran Sardick (the brilliant Michael Gambon,The Singing Detective), who holds the key to the survival of the Doctor's companion, Amy Pond (Karen Gillan), and thousands of others. To crack open this miser's heart, the Doctor decides to take Sardick to Christmases Past, Present, and Future… only these journeys involve a flying shark, a deep-frozen beautiful girl, and some of the funniest dialogue in the entire history ofDoctor Who. Written by Steven Moffat, who shepherded the remarkably high-quality fifth season of the show,A Christmas Carolis bursting with clever ideas, gleeful moments of comedy, and a deft bit of genuine sadness. Smith has settled into the role of the Doctor with aplomb, tossing off wild curlicues of rapid-fire thought with boyish zip and sly timing. This is an outstanding episode of an engaging series that deserves a much wider following. Extra features include an excellent making-of documentary and a video of a symphonic concert of music from the series.--Bret Fetzer