Writer "Dan" (Jude Law) likes to spend his evenings, when not with his American girlfriend "Alice" (Natalie Portman), teasing other blokes on sex-chat sites. One night he sets up doctor "Larry" (Clive Owen) with a promise to meet at the aquarium with "Anna". The horned up physician duly turns up, only to discover that meantime "Dan" has vengefully despatched the real "Anna" (Julia Roberts) - his part time lover/photographer, to unknowingly meet him instead. Embarrassed looks, sighs and "Larry" feels like a prat but, maybe the outwardly rather aloof "Anna" is interested? What now ensues is all ...