The party was awakened by the soft kiss of the mother star in the morning. They remembered how excited they had been the night before to find the ship intact, and how they had laughed all the way to hide it in the warehouse that Thomson had told them about. Now they were poring over the recipes of several breakfasts that Thomson had kept in the backpack.

"How about this?" Photon asked Natalie, pointing to the pork chop burger.

"Well, what a lot of heat! Aren't you afraid that gaining weight will affect your performance?" Natalie replied, disgusted.

"You two can't eat it. You can only taste it. And we might go somewhere special today. We're going to see a lot of checkpoints, and I don't think it's going to be easy. So that's it." As William said this, Photon hurried to get out the necessary ingredients. Soon it was ready. After a hearty meal, the party prepared to move on to the next checkpoint.

The morning breeze kissed them good-morning once more as they stepped up the maple-strewn road. During just one night, it was unknown how many maple leaves had entered into the arms of the earth mother. In the distance the birds' voices were still repeated. The bright blue light of the mother star flowed through the gaps in the leaves like a clear stream of water, leaving millions of bright patches of varying sizes on the maple leaves. From a distance, they saw the next checkpoint, and they all quickened their pace.

Due that Thomson's tree house was in the middle of the forest, the road gradually widened as they came out. As the last line of maple trees fell behind them, the front suddenly opened wide. To their surprise, they found that the forest had gradually disappeared from their sight; now they were flanked by endless fields, a paradise of violets and tulips. The blue mother star now hung above them, nourishing the planet with its flowing light. The violets were dancing gently in the breeze, and a few butterflies on the petals of the tulips were attracted to look at them. Beyond that were rolling mountains, which must have been dozens of kilometers away. All they could see now was the green coat of the mountains and the white clouds that served as their caps.

"Look! Checkpoint!" Natalie said, pointing to a flashing blue light.

"Go!" The party darted past.

Checkpoint 2 is cleared. Energy charge: 2.5%.

"Yeah!" The party gave a shout of joy and galloped on.

About a kilometer later, they passed Checkpoint 3 and charged the energy core with 2.5% of the power. At that moment William stopped and tried to look forward. "Here we are." He said to the others when he saw a tall building, "That's where we're going."

"Where? Let me see." Ranran said.

"The tallest one. Let's get over there quickly."

So they went on for about ten minutes and saw a sign at the side of the road saying "3km". By this time they had reached the foot of the tall building. When she looked up, Ranran saw that the building had no windows. The exterior walls were integrated and painted gray. There was a small sign hanging near the door which said,

Come in and find out!

"The map says we need to get in." Photon said.

"Then go in!" William said as he opened the door and walked in. The others followed.

It was dark inside, but when the last person came in, the door closed automatically and the lights went on. Not far in front of them was a tall maglev elevator track, and the car stopped right in front of them. There was a big red box on the floor, and a note beside it told them to open it.

Ranran untied the golden ribbon smoothly. When the box was opened, there was an envelope inside. "Anonymous again!" Natalie said disappointedly as she took out the paper.

Yet what was unexpected was that the note was surprisingly simple. It consisted of just a few sentences:

Inserting a codon at somewhere in the gene that Thomson succeeded in obtaining would eventually result in a protein that inhibits catalase activity. Follow the tips at each floor and you'll get some of the clues. For the rest of the clues, consult Uncle Sam, who owns Garage 95.

"Oh! To get part of the clues!" Natalie saw the light.

"That's it, so let's hurry up!" As William went inside, he found a strange-shaped fragment lying on the ground.

"Where is this from?" He was puzzled. Across from him, Natalie spotted the small print on the back.

Take me to the second floor, please.

So they went up to the second floor. As soon as he stepped out of the elevator, Photon saw a hole in the wall that matched the shape of the fragment. When William put it in, he heard a crack and something fell out of the corner. "It's a key, but I don't know what it unlocks." Said William, somewhat perplexed.

"There's something behind this picture!" Photon hit a painting of dandelion on the wall. It fell off, exposing the hidden note behind it.

That was a small question,

Should the air pressure change around an organism that is using glucose as a reactant for aerobic respiration?

"No, because for every six moles of oxygen we consume we produce six moles of carbon dioxide, so the pressure is almost constant." Witty William replied quickly.

The note fell off itself. There was another key in the back, but it was a different color.

"We'd better put them away. They may come in handy somewhere." Natalie said.

They continued to take the elevator up to the third floor. In front of them was a table made of rosewood, half a man's height. In the nearby yellow light, the circular texture on it was clearly visible. There was a red telephone on the table, whose panel was padded with a transparent film, but because it had been placed for a long time, there had been a layer of dust. In addition, the phone line had disappeared.

Photon opened two drawers under the desk. There were notes in them. The handwriting was strikingly similar to all the others they had read:

Don't worry, the phone line is hidden somewhere in this building. When you find a small box, please take it down. There will be a million-meter bill in there. In addition, one note will have a phone number. Dial that number, slip the bill through the pipe, press the red button and wait for a moment. And then you get another key.

"So that's it," William muttered, as Natalie noticed something poking out of the wall. Ranran took it out. It was a package with a magnet inside. Ranran turned around. Behind her was a table with a complex set of mechanisms. In the corner of the table was written,

As long as you can use this set of mechanisms to turn the light on, you can get the key.

"Ah, what's this?" Ranran asked with some puzzlement.

William came over to take one look and said, "You can sweep this magnet over the track parallel to it."

Ranran did as she was told. The metal rod began to accelerate, fell off the end of the track and landed on a minitype seesaw. A ball at the other end bounced up and landed perfectly on the track. After a few turns, when it slid out of the track, it pressed down on a switch. As a result, the light in the corner of the table lit up, and a notch opened automatically at the same time, then a key popped out. William caught it at once.

"It's called electromagnetic drive." William gave a confident smile.

On the fourth floor, on a sofa, they found the box with the bill, the phone number, and, surely, a key.

"But now we don't know where the telephone line is!"

"Natalie, let's see what this is first." Said William, pointing to a small blackboard.

As they drew near, the words appeared,

If you can answer this correctly, the phone line is in this safe box. It will open automatically.

There is a decimal x. Plus it 1, divide it by 3, minus it 7, then times it by 4, then square it, and we call the number we get N. N meets the following conditions:

N is a five-digit number like ABCDE, and there is no identical number; A + B + C = C + D + 1 = K, and the hundreds and ones place of K ^ 2 are both the number m, and the tens place is m + 1; There are three even numbers in A, B, C, D and E; The mantissa of D ^ 287 is 2; E / 5 can be used as the eccentricity of a hyperbola; If the mantissa of e ^ 2 is denoted as t, then t - d = - (a + c); B ! is equal to 3 times (e - 1).

What is the decimal x?

"Wow, what's this?" When the others saw this question, they were all puzzled.

"Don't be afraid. Let's analyze it together." William took his time to say, "According to the question, n should be a perfect square, or x would be irrational. We can see the third condition, from which we get D = 8."

The others nodded.

He went on to say, "OK, so if we plug it in to the first condition we will see that c = 2 and a + b = 9. We know that the sum of two numbers with the same parity has to be even, and now we only have one even number left. So, the parity of A and B must be opposite, that is, they are odd and even."

"Is the eccentricity of a hyperbola always greater than one?" Guessed Photon.

"Yes, I remember that clearly." Natalie said proudly.

"Stop! That's all you know."

"Hum! It's not true!" She said crossly.

"So it looks like e is greater than 5. Since n must be a perfect square, e must be 9." Said William again.

"Why? Can't it be 6?" Ranran asked.

"Since the even number is already somewhere between a and b, e must be odd."

"Oh, all right. So t is going to be 1. Substitute the values of c and d into the fifth condition, and a = 5."

"No problem, Ms Ranran. Only the sixth condition is left, but what does that B ! mean?" Photon asked her in puzzlement.

"That's factorial, which means to multiply from 1 all the way to B." Smiling, she explained, "If you plug in e, you get b = 4."

"So the five-digit number is... 54,289. Whose square is it?"

Before William could finish saying, Natalie ran the computer and figured it out: it was 233's square. So after some calculation, William typed in: x = 194.75.

The safe box opened with a snap. Inside was a red telephone line and a note with a phone number. "Let's go assemble it!" They went downstairs again, put together the telephone line, and dialed the number on the note. Photon quickly stuffed the small box containing the bill into a pipe.

A few clicks later, a deep voice came from the other side of the phone, "OK..."

"Click!" William said, hanging up the phone. Photon tapped the red button with the wingtip and with a whoosh, the box skyrocketed.

"Well, that should do it." Ranran said with a sigh of relief.

A minute later, they heard "Whoosh!". Photon saw the box come back. This time, there was a key inside.

Then a desk drawer suddenly opened itself, startling them into a cold sweat. A note flew out of it and landed on William's hand. He opened it and read, "The keys are all here... Now you go up to the top of the building and then you can go out... Oh, good! Let's go upstairs!"

The elevator took them to the top of the building. They walked up a short flight of stairs, used the keys to unlock a door, and saw a circular opening ahead. There was also a note on the ground.

This is a slide. The exit would be on the grassland behind Sophia's cafe, two kilometers away.

They entered in turn. When the last person climbed in, the slide entrance suddenly closed.

William was enjoying the speed when a note hit him in the face.

"What is this..." He took it down and saw a piece of most important message on it,

Codon insertion position: DNA#18~#19

Codon first digit: G

Codon medium digit:?

Codon last digit:?