Clarke stars as Kate, a messy, London-based clerk who works at a year-round Christmas store where she must dress like an elf.
Kate's whirlwind life takes a turn for the better when she meets Tom (Golding), who helps to open up her heart. As the pair continue to get close, Kate shares with Tom her health issues and how she had a near-death experience.
"As London transforms into the most wonderful time of the year, nothing should work for these two. But sometimes, you gotta let the snow fall where it may, you gotta listen to your heart," reads the synopsis.
Last Christmas, from director Paul Feig (Bridesmaids), is set to arrive in theaters on Nov. 8.