In 2006, Dr. Kate Forrester (Sandra Bullock) is leaving a lake house that she has been renting in Kenosha, Wisconsin to move to Chicago. Kate leaves a note in the mailbox for the next tenant to forward her mail, adding that the paint-embedded pawprints on the path leading to the house were already there when she arrived. Two years earlier in 2004, Alex Wyler (Reeves), an architect, arrives at the lake house and finds Kate's letter in the mailbox. The house is neglected, with no sign of paw prints anywhere. During the subsequent restoration of the house, a dog runs through Alex's paint and leaves fresh paw prints right where Kate said they would be. Baffled, Alex writes back, asking how Kate knew about the paw prints since the house was unoccupied until he arrived. On Valentine's Day 2006, Kate witnesses a traffic accident near Daley Plaza and tries to save the male victim, unsuccessfully. She impulsively drives back to the lake house, finds Alex's letter and writes back.