CHOW CHI YU (Wu Myolie) once adopted a stray dog TAI PA but it brought virus to her father's kennel and all the dogs inside are dead tragically. Since then, her older brother CHOW CHI JIM (Lui Fong) and sister-in-law SHUI TIN LAN (Tsang Wah Sin) have no choice but to open a pet shop for a living. Later, YU met TAI PA's little brother SIU PA but her boyfriend YING HOI LEUNG (Wong Ho Yin) suggested her to keep it in an empty house nearby.
MIU CHUN (Lo Ka Leung)'s girlfriend KAKA lost her life while saving her dog TAI PA in a traffic accident. CHUN was devastated and he abandoned the dog while keeping KAKA's beloved cat CANCAN with him. CHUN moves in to his new home but he is enraged to discover SIU PA has been raising there secretly by YU, his neighbour as well as his coworker at advertising firm. While seeing each other day and night, the battle between the 'cat' and the 'dog' becomes never-ending.
CHUN accidentally uncovers a secret relationship between YU and LEUNG. YU turns to CHUN for advice since she