Polina woke in an unfamiliar place with small lights and a few empty beds. The headmaster sat next to her bed dozing quietly with one of his hands resting on her blanket. She sat up abruptly and woke the man startlingly. "Welcome back Polina, how are you feeling. Glad to see you are healthy again," Gustaf told her.

"Uhm, what happened, all I remember is eating dinner. Now I am here in what is the medical section. It seems like the middle of the night and my stomach aches and feels empty. Can I get some food and go back to my bed?" A groggy Polina whispered.

Gustaf took Polina's hand and patted it softly reassuring her that things were safe and under control. "You must stay here until morning and allow the doctor to check you then sign your release. There is a sandwich next to your bed with some water. That is all you can have for now. We think we know what happened to you. The investigation continues, but it is similar to the earlier poison. Glad you are back. Eat a little and go to sleep. I will stay by your bed."

Polina sat on the edge of her bed, voraciously ate her sandwich and cautiously drank the milk. She burped loudly and laughed, but hid her embarrassment from Gustaf, who smiled. The eating tired her, and she slid under the blanket, curled up on her side and was quickly back to sleep.

A lab technician quietly entered the medical ward and approached the headmaster. He handed Gustaf a note with the results of the poison analysis. As Gustaf read the results, he shook his head in disgust because it confirmed his suspicions. The poison was the same as the earlier incident, and he knew who "accidentally" delivered the previous dose was responsible for this one too. As he sat beside Polina, he wondered what he should do to punish the people, but not allow this uncontrolled rivalry to continue. For right now, it was only pranking, but based on the poisons and the small bomb accident, it could escalate into harmful "accidents." He decided to talk to Marcia and her friends when Polina joined the group again. The discipline would start with them and continue through with the whole class.

While Polina recovered, Naomi and Stefan talked with Marcia about the incident. They knew Daria was the instigator of the attempt. They silently agreed that Daria had to pay for her villainy. The revenge has to hurt but not destroy things. Naomi offered to make a remotely detonated bomb that would make a lot of noise and maybe singe hair. They agreed that a small bomb would send a message but not maim her. The only problem was when and how to deliver it.

As the trio of friends sat around the lab table, Naomi watched Daria and Franci as they chattered and waved things around. Daria kept a round box of candy and popping one in her mouth. The candy gave Naomi an idea for the revenge prank on Daria. She gathered Marcia and Stefan in a huddle to explain her idea. She told them of her plan to make a small flash bang bomb in a candy box. When Daria opened it, there would be a bright flash and a loud bang, but no damage to people or property. Marcia smiled at the idea, and Stefan clapped his hands in glee.

Once they decided the revenge prank, they made a list of things they needed. They had flash-bang powder, the fuse and detonator and paper to wrap it tightly in a compact package. The needed a container and a spring switch to start the explosion. Naomi looked around the lab and found a small switch that would work when opened. All she needed was the container for all the components. She looked around but found nothing that Daria would see as interesting.

Naomi observed Daria a little more and thought about what would catch Daria's attention. Daria kept eating candy out of a small circular box made of card stock. Naomi thought, "If I only had a candy box, it would make the ideal bomb." Daria suddenly took the candy box and tossed it into the trash container at the front of the lab. Naomi smiled she had the ideal container. She quickly went to the front of the lab grabbed some paper and retrieved the empty candy box.

Naomi ran back to her table gleefully smiling in victory. She had everything she needed to exact revenge for Polina's 'accident.' She carefully put all the elements in her personal locker at the lab table and locked it. Stefan and Marcia worked together on the next lab project and had not noticed Naomi sneak away to get the box. When Naomi moved closer to them, Marcia looked up and saw Naomi's giddy appearance.

"What is going on? You look as if you scored a huge victory." Marcia smiled at Naomi.

"I guess in a sense I have. I am ready to build the revenge prank. All the material I need is in my locked lab box. All I need is time to assemble it. I plan to start it tomorrow after Polina returns. She can see it and help if she wants."

"Stefan and I can work on the next project and complete it. You and Polina can build the flash-bang bomb. We will have to plan how to execute the prank without drawing attention to our group. I think the headmaster knows who poisoned Polina and plans to discipline her. We could make the prank and her punishment work together to humiliate her more. We have a meeting with the headmaster tomorrow. He will tell us what we want to know. Let's try to finish this lab assignment today."

"It is almost time for lunch. I think Polina will be back with us at the table, and we can tell her then. I can't wait to see her face when we tell her, what happened and what we plan."

The trio entered the dining area and saw Polina sitting at a table waiting for them smiling and happy as she waved them over. They went to the line, picked out their lunch and joined Polina. As her classmates entered, they waved and smiled to see her recovered and well. When Daria and Franci entered, they scowled to see her at the table with her friends. Lunch proceeded joyfully, and Naomi tried to get Polina alone, but the class kept her away.

Finally, after lunch, the group gathered around their lab table, and Naomi spoke to Polina. "Do you know what happened to you? Daria and Franci poisoned you, hoping to keep you away from class for a few days. It is close to the end of summer school, and they hoped you would not finish our group project."

"They would not do that to me. I am Daria's oldest friend, and she protected me growing up. Why would you think that?"

"Think about what you did before you were poisoned. You got a refill of your drink. While you were there, Daria distracted you and Franci poured the poison into your glass. You took a big gulp and returned to the table where you passed out."

"Hmm, I guess you are right, but I am not sure."

"Well, I am building a small prank flash bomb to leave for the two of them to find. It won't hurt anyone, only a bright flash and loud bang."

"Are you sure they did it? I don't want to prank them, if it was someone else, although, they deserve to have something done to them on general principle. Can I help put the prank together? I want to learn more about making bombs with you, Naomi. Have you gathered everything you need?"

Naomi opened her lab storage drawer and showed Polina the pieces she gathered for the prank. Polina examined them and approved of what she saw. Naomi took the flash powder and the small amount of explosive, wrapped it in paper tightly with a percussion cap and sealed it with a very short exposed fuse. Polina, meanwhile, put together the trigger mechanism to spring open when Daria opened the candy box. Naomi carefully placed the charge with fuses in the small candy box and waited as Polina added the trigger and sealed the box closed.

As Polina finished sealing the box, her hand slipped and Naomi lunged to catch the box as it fell off the table. She hit the floor hard on her stomach with her hands outstretched, gingerly caught the box and carefully held it from striking the floor. Everyone at the table released a collective sigh. Naomi quickly stood and hid the prank in her drawer. It was the wrong time to release the prank because everyone expected Polina to strike back. The prank would wait for a few days until the curiosity died down and the students went back to normal banter and forgot.

Toward the end of the fifth week of summer school, Naomi and Polina decided it was time. They carefully took the box out of storage and placed it in Daria's lab drawer just as students entered. Daria always was the last student to enter the class. She opened her drawer, saw the candy box, and smiled at the gift. Daria picked up the box and felt it was full by its weight. She still had an open box, so she put it back in the drawer. She took out her old box out and soon emptied it. She picked up the flash bomb and put it on top of her books.

Naomi and Polina watched periodically hoping to catch Daria opening the box of candy. Franci kept sneaking candy from Daria until the box on the table was empty. Daria reached into her lab drawer and drew out the new box. Naomi and Polina gasped as Daria put the box on the table and removed the sealing tape. Naomi covered her mouth and shielded her eyes in anticipation of the flash; Polina ducked down. The box was untaped, but Daria put it down before opening it.

Franci wanted a candy and asked Daria for one. When she twisted the cover off and opened it, there was a bright flash and loud bang. Daria screamed, Franci ducked, and the rest of the class screamed in fright. No one saw Naomi and Polina turn to their friends with broad smiles covered by their hands. The prank worked perfectly scaring Daria and Franci, but doing no physical damage.

When the flash erupted followed by the loud bang, several lab technicians ran into the room ready to aid the stricken children. What greeted them was a pair of girls shaken but unharmed and their classmates all smiling or giggling. The prank worked perfectly, and the intended targets got the message. The revenge prank satisfied Polina for her poisoning. Naomi and Marcia felt it was not enough, but had no idea what else they could do. Marcia knew that this was not the end to the pranks.

The headmaster cancelled classes for the remainder of the day and called Marcia and her friends to his office to discuss the incident. He knew who did it and was sympathetic to them, but needed, at least, to appear to punish the students. Having them meet in his office was the best idea.

As the group entered his office, they all stood at his desk looking at the floor. The headmaster stood, and his eyes moved from student to student before he spoke. "I do not know who built that bomb, but your group is the only one advanced enough to design and build it. It was a good prank and much deserved by Daria and Franci, but I need to punish someone. When you leave here, please appear as if I severely reprimanded you. Be aware that I will watch you closely until the end of school and we leave this island.

Everyone relaxed with a collective sigh of relief. The headmaster sat, and the students pulled up the chairs in the office and sat. For the next thirty minutes, the conversation focused on the experiences of summer school. The headmaster asked questions about the classes and the topics covered. He was curious about spirits and other strange things on the island. Marcia was the only member who felt any of the spirits. The rest only told about what they saw