EJ 10 swallowed hard and looked at the screen. She bit her lip nervously as she looked at the numbers.

For a moment EJ could only stare blankly at the screen. Her eyes went fuzzy and the numbers seemed to blur and crash into each other. Then she remembered her practice on the code-machine. She’d seen this code before and somewhere else … but where? EJ thought hard and then it came to her.

‘It’s the same as in my maths test!’ she cried. ‘I think the numbers stand for letters. A=1, B=2 and so on all the way through the alphabet.’

‘Okay,’ said Captain C. ‘Let’s see. Light Screen, run text through letter-substitution code using solution A=1, B=2.’

The screen flashed and two lines of words appeared on the screen.

‘I’d say you just cracked your first mission code, EJ10,’ said Captain C, looking impressed.

But EJ was disappointed. ‘But what does it mean?’

‘You’ll find that cracking the code is sometimes only the start of solving the puzzle,’ said A1.

‘I can help with one part,’ said Captain C. ‘The bay must refer to the bay we are in. Someone wants us to stay here in the bay.’

‘And that must be SHADOW,’ said A1. ‘But what are they up to? What are these “five hawks”? There is something else going on.’

Suddenly lights started to flash all over the monitors. The black circle on the map quickly got larger.

‘Whatever else they are doing, we need to stop this spill now,’ said Captain C, ‘or it will do untold damage to the marine life in the bay. Hundreds of seals, turtles, birds and fish are at risk, A1. We need to take action now. It’s time to launch Aqua-Vac.’

‘Yes, it is,’ agreed A1. ‘Aqua-Vac is a rapid-response water-cleaning process invented by our Science and Invention Division,’ she explained to EJ. ‘They are giant, vacuum cleaner-like super-suction devices that attach to boats and, literally, vacuum the water, lifting the oil from the water or coastline. Captain C, how quickly can you deploy Aqua-Vac?’

‘The hull is opening now,’ said Captain C. ‘It holds ten microlight speedboats, all fitted with Aqua-Vac. If we spread them out we can have this spill under control before it does any more damage, and while the microlights clean up the bay we can look after any affected animals.’

‘Excellent,’ replied A1. ‘Ready, EJ10?’

EJ nodded. She didn’t think about being scared, she just thought about needing to help save animals.

EJ and A1 and the other rescue agents were lowered down the side of Shining Light 2 where the speedboats were waiting. A1 and EJ stepped into the first boat. A1 pushed a button on the dashboard and four large pipes, two on each side, came out from the side of the boat. A1 pressed another button and there was a loud sucking sound.

‘The pipes suck in the water, just like a vacuum cleaner, EJ,’ shouted A1 over the noise. ‘Then a converter inside separates the oil from the water and then ejects the cleaned water back into the sea.’ She pushed the button again and the pipes pulled back into the boat. ‘We will activate once we reach the spill zone. Okay, let’s go!’

There was a roar as A1 and the other agents all started their engines. The boats cruised away from Shining Light 2 before accelerating and then fanning out in all directions, bouncing along the top of the waves.

‘Check the map on the dashboard,’ cried A1. ‘You can see when we approach the spill zone. We will then activate Aqua-Vac.’

EJ could feel the water spray onto her face as they bumped over larger and larger waves. She ducked and turned her head to avoid getting water in her eyes. It was then, as she turned, that she saw five large ships, in a row like ducks, on the horizon.

Captain C said it’s unusual for ships to travel together, she remembered. She took the binoculars from the boat’s dashboard and looked again towards the horizon. She saw that the ships were tankers and that each had a letter and numbers painted on the side.

‘What are you looking at, EJ?’ asked A1.

‘There are five tankers out there,’ said EJ. ‘Captain C said that tankers don’t normally sail close to each other.’

‘Interesting,’ said A1, slowing the boat.

‘And each tanker has a letter then numbers painted on the side,’ said EJ.

‘That will be their names,’ explained A1. ‘Some ships have names like Shining Light, others have letter or number series.’

‘Yes but there’s something else about these ones, I think,’ said EJ. She adjusted the binoculars and gasped at what she saw. All the ships were flying a flag, the same flag, a white flag with a black hawk on it.

‘Black hawks!’ she cried. ‘All those tankers are flying flags with black hawks. Remember the message we intercepted? And those letters on the side are S, H, A, D, O,’ she said. ‘SHADOW?’

A1 stopped the boat.

‘I like your thinking, EJ. But that’s only SHADO.’

‘Yes but these are the five tankers, there’s one more,’ realised EJ. ‘The “last” in the message. I’m pretty sure if Captain C looks for a tanker with a W on its side, she will find where the oil is coming from.’

‘Of course S-H-A-D-O and W makes SHADOW. Good work,’ said A1. ‘It makes sense now. The last tanker stayed in the bay dumping oil so we would have to stop it while the others, the five black hawks, got away.’

‘But with what?’ asked EJ.

‘I’m guessing the missing oil from the pipeline,’ said A1. ‘I will get Captain C on it. It won’t be hard to locate the sixth tanker now that we know what we are looking for.’

EJ felt proud of herself. She had cracked the code and found SHADOW and she hadn’t even finished her basic training. She looked up at A1 who was just putting down the radio and turning off the boat engine. EJ wondered why she wasn’t smiling anymore.

‘A1, what is it?’

‘Shining Light 2 has already spotted the tanker and will be able to find it easily,’ replied A1.

‘That’s good, isn’t it?’ asked EJ.

‘Yes, EJ, it is,’ said A1. ‘But Captain C had some bad news. They found another seagull and its gull-cam has some disturbing footage from the seal breeding grounds, on the coast, less than two nautical miles from here.’

‘I know that place,’ said EJ. ‘We visited it on a school excursion. There are hundreds of seals there. And seal pups.’

‘That’s right,’ continued A1, ‘but the oil spill has separated the mothers from the seal pups. The mothers were out fishing while the pups waited on the rocks but the slick now lies between them. The mothers will not be able to get back to their pups unless they swim through the oil.’

‘They’ll die if they do that!’ cried EJ.

‘Yes, if the oil coats their fur they could drown and if the oil reaches the pups it will mask their smell, so if the mother does make it back she would no longer recognise her pup.’

‘The whole seal colony could be lost,’ realised EJ.

‘It gets worse. The footage from gull-cam shows that some of the pups are trying to leave the rocks to find their mothers. We need to stop the mothers swimming into the oil, Aqua-Vac the area and rescue the pups.’

‘But how can we do all that at the same time?’ said EJ. ‘It’s hopeless.’

‘No, just difficult,’ replied A1. ‘We need a plan. What do we know about seals?’

EJ thought back to her school excursion. ‘Seals love fish,’ she said. ‘So, we could … no it’s a dumb idea.’

‘There’s no such thing,’ said A1. ‘Go on.’

‘Well, if we had fish, lots and lots of fish, perhaps the seals would follow us and we could lead them away from the oil?’

‘I like your thinking, EJ10,’ said A1, taking two charms from her bracelet. ‘And, thanks to the Science and Invention Division, I have just what we need.’