It is said that after Yang Zi jumped into the taxi, he said to the driver without hesitation: "Master, go to the Chengnan Ferry Terminal." It turned out that when he calmed down and listened to the background sound coming from the phone, his mind suddenly recalled some of the principles of sound that he had learned when he was studying physics in middle school.

In physics, the propagation of sound requires a medium, and the speed at which it propagates in different media is not the same, and the speed of sound propagation varies because of different media, generally speaking, the rate of propagation of sound in a medium is greater than that of a liquid in a solid, and slower than in both a solid and a liquid in a gas.

In the air, sound travels approximately 340 meters per second. Because the sound in different media, the speed of propagation is different, so the phenomenon of reflection and refraction of sound is generated, and the phenomenon of reflected sound waves encountering obstacles in the process of traveling, and cannot pass through and return to the original medium is called reflection, and this sound wave reflection phenomenon is also called echo.

Therefore, when Yang Zi answered the phone, he first felt that the voice of the other party from the phone was relatively quiet, indicating that when the other party was talking, there was no appropriate obstacle around to form the conditions of echo reflection, and in the process of sound wave propagation, under the action of wind, the sound wave did not have echo reflection, resulting in a smaller speaking sound than in other places, so it can be affirmed that the other party's position is in an open place outside; Secondly, from the beginning of receiving the call, in addition to the sound of talking, there is always a whirring wind coming out of the phone, such a loud wind can be heard by Yang Zi through the phone, combined with the first consideration, the eligible place is either on the top floor of a certain building, or in a secret place on the south side of the river in S City, and then it is in the west suburbs of the city, but considering that talking in the mountain will definitely produce a certain echo, so the choke horse mountain is excluded by Yang Zi, so that only the two places mentioned above are left; Last but not least, in the five minutes when the other party didn't speak and let Yang Zi listen to the background sound, Yang Zi just heard a long whistle, which came out of the phone clearly, and the sound was as close as if a river ship was driving next to Yang Zi.

Judging from this, the kidnappers must have been by the river, and at the same time, after the whistle sounded, Yang Zi vaguely heard the sound of the electric bell that prompted the opening and closing of the gate and the sound of the ferry staff directing the flow of people up and down the pier with a loudspeaker after the ferry docked at the ferry terminal.

Based on these, the experienced Yang Zi concluded that the kidnappers must be at the ferry terminal. But he suddenly felt very strange, why didn't this kidnapper play his cards according to common sense?

Just imagine, a kidnapper kidnaps a hostage, for the sake of his own safety, he will inevitably use various means to imprison the hostage, restrict the hostage's personal freedom, and prevent the hostage from knowing his true identity.

These methods include tying up hostages, covering their eyes with black cloth, taping their mouths or stuffing rags to prevent them from calling for help.

At the same time, because the hostages are detained, it will inevitably cause inconvenience, and usually, the kidnappers will choose a very secret place to facilitate the guards and prevent the hostages from escaping; secondly, to reduce activities as much as possible to avoid exposing the horse's feet and being discovered by others when carrying hostages with reduced mobility; Sanma hides himself and the hostages, so that he can hide in the dark to observe the situation and take corresponding actions according to the situation.

But this one is good, openly swaggering with hostages to stay near the crowded ferry terminal, what kind of play is this?

The more Yang Zi thought about it, the more strange he felt, and while sitting in the taxi, he habitually put his hand on the door of his head and tapped gently.

Although he judged that the kidnapper's location was near the riverside ferry terminal, but this area is not big or small, is it true that the kidnapper took that trick, the more dangerous the place is the safer place, and he really stood at the entrance and exit of the ferry with hostages?

Cut~~, Yang Zi himself felt that it was unlikely, and gently shushed himself in his heart. The question is, where is the location?

Seeing that the taxi was getting closer and closer to the dock, Yang Zi couldn't help but feel a little anxious, and he always had an indescribable feeling in his heart, which was very strange, making him feel that all this was too unreal, as if he was dreaming.

He even had a thought in his mind that even he thought was incredible, that this so-called kidnapping was not real, that it was playing a prank on him, and that thought would not go away anyway as soon as it appeared in his mind.

No matter how he reminded himself, he must be cautious and careful, the other party has a living person in his hand, and if he doesn't do it, he will die, but this thought is as stubborn as if it has taken root in his mind.

Just when he was a little distracted, the taxi had already arrived at the gate of the ferry terminal, and the driver turned his head sideways and gently reminded him: "Comrade, it's here." It was too late to think about it anymore, Yang Zi suddenly bounced up from his seat, paid to push the car door and jumped out of the car.

He stood at the entrance and exit of the ferry terminal, looking at the people who were stopping at the gate one by one with a scrutinizing eye, and after checking that no one showed any special concern for his arrival, Yang Zi turned his gaze to the sides of the gate again.

Here is a couple whispering, and a few students are talking about something together; There were two girls pushing and pulling each other while waving their things, and an old man was eating while reading a newspaper.

No, not here, but where could it be? Yang Zi's heart began to get anxious. Suddenly, his mind moved, and he turned around and walked briskly towards the water park, which was two hundred meters away from the gate of the ferry terminal.

He walked a few steps to the entrance of the water park, by which time night had fallen, but as the most representative amusement park in the city, the water park was still brightly lit, most of the tourists had dispersed, and a small number of people remained in the park.

This park is not big, it only takes a few steps to walk to the riverside as soon as you enter the door, mainly a corridor is built on the riverside, and some tables and chairs are placed for visitors to enjoy the scenery while drinking tea, and some entertainment facilities such as yachts are attached for visitors to play.

After Yang Zi entered the door of the park, while looking around, he took out his mobile phone and tentatively called back the phone just now.

Unexpectedly, the phone was connected, and on a yacht moored by the river, there was a burst of melodious songs with Lin Junjie's "Laughing Eyes" as the ringtone of the mobile phone: "I only found out after leaving you, the laughing eyes shed tears, like a storm that can't be avoided, and the wet yesterday was deleted." I didn't find myself until I left you, those smiling eyes, when I see you again, I will let myself, let myself be firm. When I see you again, I will let myself pretend to be very determined. But the owner of the phone did not answer or refuse to answer the call, but only allowed the song to ring abruptly in the gradually cold night.

Yang Zi changed the phone that was still in the state of calling out to his left hand, and his right hand quietly stretched out to his waist, pressed it on the pistol holster hanging there, and while preparing to return fire with a high degree of vigilance, he walked slowly and slowly towards the place where the voice sounded step by step with a very slow but firm pace.