Sherlock holmes S05E01 STORY part 3

Mycroft : come on ..come in and  take your seat. Its impossible to plant the bomb before the summit or roll in with bomb.
Sherlock : thats what I am thinking how can this be possible.
After sometime the crew of officials of both the country arrived and prime minister also reached there. The speech were delivered from both side. Sherlock was still in the puzzle. Both the officials came forward for signing the treaty.
Sudden Sherlock came on the dice and took the pen in hands of prime minister and said thank you.
Mycroft : what you doing ??
Sherlock : please have another thats mine.
He left the place
Watson : what was that? Is everyone safe?
Sherlock : yeah everyone is safe now( and pointing towards the pen)
Watson : what's special in this ?
Sherlock : this the scientists formula bomb. Because everything in the summit was checked very minutely except prime minister accessories thats clicked me . one more thing I remembered myroft told there was problem in pen for signing the previous treaty.
Watson : I don't have words for you . awesome

The end