Imps 48-board KO, last set of 8 boards, you were 22 up before the start of this 8-board set and it's the fourth board, so far you have had two normal-looking boards and one +100 when you were cold for a NV game, but it looked exceptionally hard to bid.
Auction starts with you
1NT (15-17) P 2♦ (xfer) 3♣
3♦* P 4♦** P
4♥ all pass
3♦ = undiscussed, you think it ought to show diamonds and hearts
4♦ = undiscussed, either raising diamonds or a re-transfer if partner has hearts
LHO leads the Ace of clubs (RHO plays a discouraging club)
LHO continues with the 10 of clubs.
This is a rather nice start.
Plan the play.
edit: fixed a pip error
4♥ by South