diff --git a/x/cardchain/keeper/msg_server_set_card_add.go b/x/cardchain/keeper/msg_server_set_card_add.go
index 738c9cae..3411f9a4 100644
--- a/x/cardchain/keeper/msg_server_set_card_add.go
+++ b/x/cardchain/keeper/msg_server_set_card_add.go
@@ -2,16 +2,60 @@ package keeper
 
 import (
 	"context"
+	"slices"
 
+	errorsmod "cosmossdk.io/errors"
 	"github.com/DecentralCardGame/cardchain/x/cardchain/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/types/errors"
 )
 
 func (k msgServer) SetCardAdd(goCtx context.Context, msg *types.MsgSetCardAdd) (*types.MsgSetCardAddResponse, error) {
 	ctx := sdk.UnwrapSDKContext(goCtx)
 
-	// TODO: Handling the message
-	_ = ctx
+	setSize := int(k.GetParams(ctx).SetSize)
+
+	set := k.Sets.Get(ctx, msg.SetId)
+	if !slices.Contains(set.Contributors, msg.Creator) {
+		return nil, errorsmod.Wrap(errors.ErrUnauthorized, "Invalid contributor")
+	}
+	if set.Status != types.CStatus_design {
+		return nil, errorsmod.Wrapf(errors.ErrUnauthorized, "Invalid set status is: %s", set.Status.String())
+	}
+
+	iter := k.Sets.GetItemIterator(ctx)
+	for ; iter.Valid(); iter.Next() {
+		idx, coll := iter.Value()
+		if coll.Status != types.CStatus_archived && slices.Contains(coll.Cards, msg.CardId) {
+			return nil, errorsmod.Wrapf(types.ErrCardAlreadyInSet, "Set: %d", idx)
+		}
+	}
+
+	card := k.Cards.Get(ctx, msg.CardId)
+	if card.Status != types.Status_permanent {
+		return nil, errorsmod.Wrap(types.ErrCardDoesNotExist, "Card is not permanent or does not exist")
+	}
+
+	if card.Owner != msg.Creator {
+		return nil, errorsmod.Wrap(errors.ErrUnauthorized, "Invalid creator")
+	}
+
+	if len(set.Cards) >= setSize {
+		return nil, errorsmod.Wrapf(types.ErrInvalidData, "Max set size is %d", setSize)
+	}
+
+	if slices.Contains(set.Cards, msg.CardId) {
+		return nil, errorsmod.Wrapf(types.ErrCardAlreadyInSet, "Card: %d", msg.CardId)
+	}
+
+	err := k.CollectSetConributionFee(ctx, msg.Creator)
+	if err != nil {
+		return nil, errorsmod.Wrap(errors.ErrInsufficientFunds, err.Error())
+	}
+
+	set.Cards = append(set.Cards, msg.CardId)
+
+	k.Sets.Set(ctx, msg.SetId, set)
 
 	return &types.MsgSetCardAddResponse{}, nil
 }
diff --git a/x/cardchain/types/errors.go b/x/cardchain/types/errors.go
index 01c25658..8acf92a6 100644
--- a/x/cardchain/types/errors.go
+++ b/x/cardchain/types/errors.go
@@ -9,6 +9,8 @@ import (
 // x/cardchain module sentinel errors
 var (
 	ErrInvalidSigner     = sdkerrors.Register(ModuleName, 1100, "expected gov account as only signer for proposal message")
+	ErrCardDoesNotExist  = sdkerrors.Register(ModuleName, 1, "card does not exist")
+	ErrCardAlreadyInSet  = sdkerrors.Register(ModuleName, 8, "Card already in set")
 	ErrInvalidCardStatus = sdkerrors.Register(ModuleName, 13, "Invalid card-status")
 	ErrImageSizeExceeded = sdkerrors.Register(ModuleName, 17, "Image too big! Max size is 500kb")
 	ErrInvalidData       = sdkerrors.Register(ModuleName, 27, "Invalid data in transaction")
diff --git a/x/cardchain/types/message_set_artwork_add.go b/x/cardchain/types/message_set_artwork_add.go
index 8f2bab55..917bfed0 100644
--- a/x/cardchain/types/message_set_artwork_add.go
+++ b/x/cardchain/types/message_set_artwork_add.go
@@ -1,6 +1,8 @@
 package types
 
 import (
+	fmt "fmt"
+
 	errorsmod "cosmossdk.io/errors"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
@@ -21,5 +23,10 @@ func (msg *MsgSetArtworkAdd) ValidateBasic() error {
 	if err != nil {
 		return errorsmod.Wrapf(sdkerrors.ErrInvalidAddress, "invalid creator address (%s)", err)
 	}
+
+	if len(msg.Image) > ArtworkMaxSize {
+		return errorsmod.Wrap(ErrImageSizeExceeded, fmt.Sprint(len(msg.Image)))
+	}
+
 	return nil
 }