Phantom - Jo Nesbø

The previous book, The Leopard, had already had a sad feeling about ruined family; and now in Phantom there was even more a tragic situation. Harry Hole's girlfriend's son, Oleg, who considered Harry as his own father, was in jail for killing his friend, Gusto. Those who read this series from the beginning would know that Harry loved Rakel and vice versa and it was so sad that they couldn't be together, that Harry could not become Oleg's [step] father. Oleg, who had been grown up and became a young man, befriended a troubled teenager named Gusto and later these two friends became drug sellers. When Oleg first appeared in The Redbreast, he was just a little boy, and now in Phantom, he was as tall as Harry Hole.

After leaving the Crime Squad, Harry Hole lived well in Hong Kong, worked as a debt collector. He returned to Oslo to investigate Gusto's murder because it was impossible that sweet Oleg could murder anyone, let alone his friend. In his investigation Harry would solve several puzzles (including the identity of the mysterious Dubai, Gusto's boss), but only in the very end he finally found the real killer of Gusto. Unlike previous books, since he was not a policeman anymore, Harry acted without a partner.

This book is called Phantom because of Dubai, Harry's main enemy, was like one. This Dubai monopolised narcotics market in Oslo with heroin-like opioid violin, a very strong drug. "All she had heard about Dubai were the same rumors about his flitting around town like some kind of phantom and that no one knew who he was or what he looked like, and that he was like the wind, impossible to catch."