The only thing London couple Celeste and Sean have in common is their son, Harry. When Celeste discovers her husband's journal on his computer one night after he has gone to bed, she guesses his password and begins to read. She is both intrigued and infuriated by what she discovers. Apparently her husband, who is the full-time caregiver for their two-year-old son, resents her working all the time as a successful fashion buyer. He also repeatedly mentions a particular woman from the toddler playgroup, which makes Celeste jealous and also causes her to want her own flirtation.

Celeste's therapist encourages her to talk about her sexual fantasies during every session and wants her to keep reading Sean's journal. At her therapist's urging, Celeste begins her own secret diary on the computer to record her feelings about Sean's entries. In real life, Sean and Celeste may not feel like they are connecting, but their writing is filled with the frustration, passion, angst, arguments and inside jokes that their marriage seems to lack. As Sean's obsession with the playgroup mom deepens, Celeste takes action of her own.

The alternating narrative puts the whining and complaining from both Celeste and Sean in some perspective. Since she is responding to Sean's entries, Celeste often comes across as defensive and selfish, while Sean is blithely continuing his own self-reflection. Rebecca Campbell credits her own husband as the inspiration behind Sean's writing, which is a combination of weird wisdom and black humor. The novel deftly explores modern marriage and child-rearing dilemmas in an engaging format, never letting anyone have the last word, at least for more than a few pages.